I’m 100% certain you do not understand what you’re talking about if you think nihilism simply means “believing nothing”. Like google the word nihilism, and the dictionary definition they provide immediately discredits you. You don’t even have to dig into philosophy to see that you’re wrong.
That’s an utter failure of a description. Anytime you try to boil an entire philosophy down into its prefix and suffix, you are doing a disservice to the philosophy.
Go read Nietzche, and then actually read Sartre instead of quoting the Wikipedia summary of existentialism to me, and then maybe we can have a real discussion on the topic.
If you don’t see the value in MENTIONING objective and subjective values when comparing nihilism and apathy for someone who is having trouble distinguishing them; I truly don’t think you should be engaging in philosophical discussions.
Here is a good breakdown should YOU wish to learn more than a 300 word Wikipedia summary can teach you.