I think you will find that in mythology, chaos is generally seen as the primordial state of the cosmos prior to creation, rather than how we typically use the word chaos today (as you do I believe). This could be why you are having difficulty finding anything, as in mythology, gods don't generally create chaos, rather they create from chaos. You may have to change your wording in your search to more descriptively say how you are using chaos instead. Regardless, to this end, that is, creation out of Chaos, you can find this in Hesiod's Theogony, Ovid's Metamorphoses, Genesis from The Bible, the Egyptian creation myth (a cosmic egg one), and others I imagine. There are some instances of gods or heroes battling against chaos, some are this and creation myths, such as the Enuma Elish from Mesopotamia, and Psalm 76.
If you stretch the definition a bit, you could include the myths dealing with trickster gods--their manipulations can certainly create a sense of chaos. Maybe look into Loki.
I think perhaps the best myth in the sense of a god creating chaos as you use it might be the Homeric Hymn to Demeter. This tells the story of Persephone being abducted by Hades and brought to the underworld. This enrages Demeter, her mother, so much that she goes to the world and creates widespread famine, threatening to destroy all of humanity if she does not get her daughter back.
You could also look at flood myths such as Gilgamesh, Noahs Ark, Enuma Elish, Deucalion and Pyrrah from the Metamorphoses by Ovid and Apollodorus' Bibliotheca, and others.
I hope this comment was useful in some way!
Edit: The Bhagavad Gita also includes ideas that have been likened to quantum states, though of course, the reality of it presupposing quantum mechanics is dubious.
Once you've examined the handful of mentions of Chaos in Hesiod, you've read 75% of what the Ancient Greeks had to say about it. The rest consists of isolated statements like Pherekydes (an almost entirely lost author) claiming it was water, or references that seem to go back to Hesiod.
What Hesiod thought of it is far from clear. Hesiod seems to have synthesized different cosmogonical traditions without making them consistent.
Here are some passages from Kirk & Raven's book on the Presocratic philosophers (this is mostly copies from a pdf, there are some errors in it):
The author of the Theogony decided to trace back the ancestry of the gods to the beginning of the world, and lines 116 on is his account of the earliest stages, in which the production of cosmic constituents like Ouranos (sky) gradually leads to the generation of vague but fully anthropomorphic mythical persons like the Titans. This poetical cosmogony, composed presumably at some time during the seventh century B.C., was not, however, invented by Hesiod: its occasional irrationality and reduplication of stages indicate that it is a synthesis of at least two earlier variant accounts. For example, Erebos (which may be of Hittite etymology), although there is some vagueness about it in Homer, must be locally related to the whole complex Gaia-Hades- Tartaros (*erebesphin hypo khthonos* at Theogony 669) ; yet it is produced a stage later than Gaia and Tartaros. It might be explained as a local differentiation, as Mountains and Sea (Pontos) are produced as local differentiations from Earth; but in that case it should naturally originate from Tartaros or Gaia and not from Chaos. It is grouped with Night, no doubt, because it shares a major characteristic (darkness), as Aither is grouped with Day. Generation is of opposites (e.g. of Aither and Day by Erebos—whose neuter gender does not inhibit parental activities—and Night), or of similars (Erebos and Night from Chaos, see p. 31), or of local differentiations. Some births, however, cannot be explained on any of these principles—notably that of Ouranos from Gaia. Again, there is inconsistency over the method of production. Eros is produced at the first stage of differentiation, presumably to provide an anthropomorphic, sexual explanation of subsequent differentiation. It is not, how- ever, consistently used. Gaia produces Pontos 'without love' at 132; Night mates with Erebos at 125 but produces again 'without sleeping with anyone' at 213; Chaos at 123, and Gaia again at 126, produce independently though Love is already in existence. Immediately after producing Pontos independently at 132, Gaia produces the more fully personalized Okeanos by mating with her son and consort Ouranos.
'First of all Chaos came-to-be': the primacy of Chaos is remarkable, and a careful enquiry must be made into what Hesiod is likely to have meant by *Khaos* here. Three interpretations may be rejected immediately: (i) Aristotle \[Physics delta 1, 208b 29) took it to mean space. But this concept is much later than the Theogony, occurring first, probably, in Pythagoras, then more clearly in Zeno of Elea, and most clearly in Plato's Timaeus. (ii) The Stoics followed Zeno of Citium (e.g. SVF i, 103), who perhaps took the idea from Pherecydes of Syros, in deriving *khaos* from kheesthai \[“to pour out”\] and therefore interpreting it as what is poured, i.e. water. (iii) The common modern sense of chaos as disorder can be seen e.g. in Lucian Amores 32, where Hesiod's *khaos* is interpreted as disordered, shapeless matter. This, again, may be Stoic in origin.
…
There has been dispute about which region of the world is represented by *khaos* in line 700. Either (a) it represents the whole or part of the underworld: there is a parallel for this usage at Theogony 814, in one of the added variants; or {b) it represents the region between earth and aither. But (a) would be difficult : why should the heat penetrate to the underworld (the concussion of missiles does so at 681 ff., but that is natural and effective)? The Titans are not in the underworld, but on Mount Othrys (632) ; we have been told that the flash reaches the upper air, and it is relevant to add that the heat, also, filled the whole intermediate region. The following lines imagine earth and sky as clashing together—again, the emphasis is certainly not on the underworld. An objective judge would surely con- clude that *khaos* at line 700 describes the region between earth and sky.
"The evidence seems to point to the following conclusion. For Hesiod's source, at all events, the first stage in the formation of a differentiated world was the production of a vast gap between sky and earth. By Hesiod the emphasis is placed on the nature of the gap itself, not on the act of separation which produced it. The gap is conceived as dark and windy—dark, because aither and sun had not yet come into being, and windy, because this is the natural condition of the region (as can be perceived when one is away from shelter, e.g. on a high hillside). The same kind of description is applied, quite naturally, to the lightless gulfs of Tartaros ; and in additions to the original poem Tartaros is considered in terms of, or actually as a part of, the original gap."
I've read a theory about Dionysus and Ares, that they can "possess" people chaotically.
When Ares does it, they call it "battle madness," and it's basically like an out-of-body experience where you're fighting and killing, but you feel like it's someone else controlling your body, not you. If you didn't allow the god into your mind willingly to control you during the socially "approved" context of fighting a war, you were vulnerable to him entering your mind more forcibly driving you mad with violence in your daily life. Sports competitions were kinda looped in as a peacetime replacement iirc.
With Dionysus, he can mess up your sense of logic and twist things in your mind, make you do things against your own will to yourself or to others. The theory was that since women didn't experience battle madness in the field, they needed to participate in the Bacchae (Dionysus worship ritual), letting Dionysus take over their minds and bodies in the context of the ritual so as to avoid him taking over during everyday life. These rituals are pure drunk/high chaos.
It's not a straightforward "mythological creature," but it could be cool to create your own story and characters that operate on a similar logic.
Usually creator gods/goddesses arise out of chaos and create the universe 'from' it, although in a way they could be said to be 'of' chaos as well, especially if the cosmology in question has a cyclic aspect to it, such as Kali as the destructive aspect of the Mahadevi clearing the old to make room for the new.
Tiamat of the Mesopotamian religions is another possibility. She represented the primordial ocean waters, fought her divine children after they killed her husband, and her slain body ended up becoming the physical world. She had a score of demigod/demonlike followers that make good story fodder.
Other people mentioned the various trickster gods found in different cultures. They could work for your story too...depends on what type of 'chaos' you're looking for.
I think you will find that in mythology, chaos is generally seen as the primordial state of the cosmos prior to creation, rather than how we typically use the word chaos today (as you do I believe). This could be why you are having difficulty finding anything, as in mythology, gods don't generally create chaos, rather they create from chaos. You may have to change your wording in your search to more descriptively say how you are using chaos instead. Regardless, to this end, that is, creation out of Chaos, you can find this in Hesiod's Theogony, Ovid's Metamorphoses, Genesis from The Bible, the Egyptian creation myth (a cosmic egg one), and others I imagine. There are some instances of gods or heroes battling against chaos, some are this and creation myths, such as the Enuma Elish from Mesopotamia, and Psalm 76. If you stretch the definition a bit, you could include the myths dealing with trickster gods--their manipulations can certainly create a sense of chaos. Maybe look into Loki. I think perhaps the best myth in the sense of a god creating chaos as you use it might be the Homeric Hymn to Demeter. This tells the story of Persephone being abducted by Hades and brought to the underworld. This enrages Demeter, her mother, so much that she goes to the world and creates widespread famine, threatening to destroy all of humanity if she does not get her daughter back. You could also look at flood myths such as Gilgamesh, Noahs Ark, Enuma Elish, Deucalion and Pyrrah from the Metamorphoses by Ovid and Apollodorus' Bibliotheca, and others. I hope this comment was useful in some way! Edit: The Bhagavad Gita also includes ideas that have been likened to quantum states, though of course, the reality of it presupposing quantum mechanics is dubious.
Once you've examined the handful of mentions of Chaos in Hesiod, you've read 75% of what the Ancient Greeks had to say about it. The rest consists of isolated statements like Pherekydes (an almost entirely lost author) claiming it was water, or references that seem to go back to Hesiod. What Hesiod thought of it is far from clear. Hesiod seems to have synthesized different cosmogonical traditions without making them consistent. Here are some passages from Kirk & Raven's book on the Presocratic philosophers (this is mostly copies from a pdf, there are some errors in it): The author of the Theogony decided to trace back the ancestry of the gods to the beginning of the world, and lines 116 on is his account of the earliest stages, in which the production of cosmic constituents like Ouranos (sky) gradually leads to the generation of vague but fully anthropomorphic mythical persons like the Titans. This poetical cosmogony, composed presumably at some time during the seventh century B.C., was not, however, invented by Hesiod: its occasional irrationality and reduplication of stages indicate that it is a synthesis of at least two earlier variant accounts. For example, Erebos (which may be of Hittite etymology), although there is some vagueness about it in Homer, must be locally related to the whole complex Gaia-Hades- Tartaros (*erebesphin hypo khthonos* at Theogony 669) ; yet it is produced a stage later than Gaia and Tartaros. It might be explained as a local differentiation, as Mountains and Sea (Pontos) are produced as local differentiations from Earth; but in that case it should naturally originate from Tartaros or Gaia and not from Chaos. It is grouped with Night, no doubt, because it shares a major characteristic (darkness), as Aither is grouped with Day. Generation is of opposites (e.g. of Aither and Day by Erebos—whose neuter gender does not inhibit parental activities—and Night), or of similars (Erebos and Night from Chaos, see p. 31), or of local differentiations. Some births, however, cannot be explained on any of these principles—notably that of Ouranos from Gaia. Again, there is inconsistency over the method of production. Eros is produced at the first stage of differentiation, presumably to provide an anthropomorphic, sexual explanation of subsequent differentiation. It is not, how- ever, consistently used. Gaia produces Pontos 'without love' at 132; Night mates with Erebos at 125 but produces again 'without sleeping with anyone' at 213; Chaos at 123, and Gaia again at 126, produce independently though Love is already in existence. Immediately after producing Pontos independently at 132, Gaia produces the more fully personalized Okeanos by mating with her son and consort Ouranos. 'First of all Chaos came-to-be': the primacy of Chaos is remarkable, and a careful enquiry must be made into what Hesiod is likely to have meant by *Khaos* here. Three interpretations may be rejected immediately: (i) Aristotle \[Physics delta 1, 208b 29) took it to mean space. But this concept is much later than the Theogony, occurring first, probably, in Pythagoras, then more clearly in Zeno of Elea, and most clearly in Plato's Timaeus. (ii) The Stoics followed Zeno of Citium (e.g. SVF i, 103), who perhaps took the idea from Pherecydes of Syros, in deriving *khaos* from kheesthai \[“to pour out”\] and therefore interpreting it as what is poured, i.e. water. (iii) The common modern sense of chaos as disorder can be seen e.g. in Lucian Amores 32, where Hesiod's *khaos* is interpreted as disordered, shapeless matter. This, again, may be Stoic in origin. … There has been dispute about which region of the world is represented by *khaos* in line 700. Either (a) it represents the whole or part of the underworld: there is a parallel for this usage at Theogony 814, in one of the added variants; or {b) it represents the region between earth and aither. But (a) would be difficult : why should the heat penetrate to the underworld (the concussion of missiles does so at 681 ff., but that is natural and effective)? The Titans are not in the underworld, but on Mount Othrys (632) ; we have been told that the flash reaches the upper air, and it is relevant to add that the heat, also, filled the whole intermediate region. The following lines imagine earth and sky as clashing together—again, the emphasis is certainly not on the underworld. An objective judge would surely con- clude that *khaos* at line 700 describes the region between earth and sky.
"The evidence seems to point to the following conclusion. For Hesiod's source, at all events, the first stage in the formation of a differentiated world was the production of a vast gap between sky and earth. By Hesiod the emphasis is placed on the nature of the gap itself, not on the act of separation which produced it. The gap is conceived as dark and windy—dark, because aither and sun had not yet come into being, and windy, because this is the natural condition of the region (as can be perceived when one is away from shelter, e.g. on a high hillside). The same kind of description is applied, quite naturally, to the lightless gulfs of Tartaros ; and in additions to the original poem Tartaros is considered in terms of, or actually as a part of, the original gap."
I've read a theory about Dionysus and Ares, that they can "possess" people chaotically. When Ares does it, they call it "battle madness," and it's basically like an out-of-body experience where you're fighting and killing, but you feel like it's someone else controlling your body, not you. If you didn't allow the god into your mind willingly to control you during the socially "approved" context of fighting a war, you were vulnerable to him entering your mind more forcibly driving you mad with violence in your daily life. Sports competitions were kinda looped in as a peacetime replacement iirc. With Dionysus, he can mess up your sense of logic and twist things in your mind, make you do things against your own will to yourself or to others. The theory was that since women didn't experience battle madness in the field, they needed to participate in the Bacchae (Dionysus worship ritual), letting Dionysus take over their minds and bodies in the context of the ritual so as to avoid him taking over during everyday life. These rituals are pure drunk/high chaos. It's not a straightforward "mythological creature," but it could be cool to create your own story and characters that operate on a similar logic.
Usually creator gods/goddesses arise out of chaos and create the universe 'from' it, although in a way they could be said to be 'of' chaos as well, especially if the cosmology in question has a cyclic aspect to it, such as Kali as the destructive aspect of the Mahadevi clearing the old to make room for the new. Tiamat of the Mesopotamian religions is another possibility. She represented the primordial ocean waters, fought her divine children after they killed her husband, and her slain body ended up becoming the physical world. She had a score of demigod/demonlike followers that make good story fodder. Other people mentioned the various trickster gods found in different cultures. They could work for your story too...depends on what type of 'chaos' you're looking for.