Nurgle
Tzeentch
Khorne
Slaanesh

vs

Atum/Demogorge
Set
Chthon
Gaea
Oshtur
Many-Angled Ones (including Shuma Gorath)

Assume the Chaos Gods are cooperating with one another rather than warring, and assume Demogorge is not after any of his fellow Elder Gods for his menu.