Living Tribunal wins this fight.Eternity himself is below Living Tribunal.That goes for Chaos King as well.
On a side note.If anyone is wondering why Living Tribunal didn't stop Chaos King in Chaos War, simply put that just like Eternity who is an abstract and represents Living Tribunal's face, This would mean Chaos King also represents one of Living Tribunal's face.And as an abstract, CK is just doing what he does.So LT not stopping CK in Chaos War is not because CK is more powerful than LT, but because LT views CK as part of the cosmic hierarchy.Besides, LT should have arrested Abraxas as well.But he didn't.