Mmm, while Cthulhu would be badass to fight, I doubt it. Out of all the Mythos gods, Cthulhu is probably the least Lovecraftian, though most well known. There are not a lot of characteristics mentioned that talk about how Cthulhu works, besides speaking to people in dreams. Dreams have never been mentioned in association with Nezarec, so a god who inflicts pain and agony would make more sense.