Apostles of Doom told us that Discordia (in the book Dysnoma) and Set (in the book Sutekh) are two gods of chaos and I dont get why Set is on that side.
The egyptian personification of chaos has always been and will always be Apep/Apophis. To make this more clear, Set was the champion of Ra and defended the solar bark every night when Apep attacked it. Only after Isis tricked Ra and forced him to part this realm so Osiris (her husband) could take the throne turned Set against his family (he was unwilling to submit to the brother who stole the throne and went down a dark road).
Yet my point stands, the chaos accusations came far later (Set is the god of the deserts and everthing beyond so any issues coming from the outside are his fault (like persian and roman invaders)).
Looking at it like this Set would be far more at home in the Doomphire, he is misunderstood and the quick pr of his enemys fucked him over till the end of time.
Back to my main topic:
Apep is of course one main embodiment of chaos.
Chaos itself (for example greek mythology)
Last but not least, lets remember that chaos doesnt mean evil, its rather… unorderly?