It depends, I think the distinction is more important if you're a member of an endangered, stateless nation, because in that case the term nation-state implies

It depends, I think the distinction is more important if you're a member of an endangered, stateless nation, because in that case the term nation-state implies that your people does not exist as a nation, whereas if you belong to the dominant nation within a state, then it's the other way round, it's in your interest to reinforce the idea that there's one nation (as opposed to multiple ones), and therefore prefer the term nation-state.