[Racehorse]

Atheism is a purely faith-based belief about the nature and existence of a supreme being, and as such qualifies as a religion.

Would nihilism also qualify as a religion?

[Maceman]

Would nihilism also qualify as a religion?

In a word, no, because nihilism is not specifically a belief about the nature and existence of a supreme being, although it can be a philosophy derived from the religious position of atheism.