I had a friend that was fairly confused about morality, although he was a decent person. He would only bring up thoughts that were adjacent to nihilistic concepts when a conversation was already going. He never bought into them, but I think he's still kinda epistemically paralyzed.
It is fairly obvious in his case that he feels like i.e. saving the world might be/is most likely impossible, although he hasn't verbally confirmed it. Meh. He's caught between just kinda living as he wants to and a vague, lonely concept that something more is possible and worthwhile.
I'm not coherent with my knowledge of morality enough to pull him out of it for sure, and so I haven't really tried. Potentially divisive conversations, and all. : /
I have noticed that the term 'nihilism' has quite a few different connotations. I do not know that it is a coincidence. Reputedly, the most popular connotation, and in my opinion, the least well-defined, is existential nihilism, 'the philosophical theory that life has no intrinsic meaning or value.' I think that most LessWrong users would agree that there is no intrinsic meaning or value, but also that they would argue that there is a contingent meaning or value, and that the absence of such intrinsic meaning or value is no justification to be a generally insufferable person.
There is also the slightly similar but perhaps more well-defined moral nihilism; epistemological nihilism; and the not-unrelated fatalism.
Here, it goes without saying that each of these positions is wrong.