What you're proposing sounds more like moral relativism than moral nihilism.

Ah, yes. My mistake. I stand corrected. Some cursory googling suggests that you are right. With that said, to me Moral Nihilism seems like a natural consequence of Moral Relativism, but that may be a fact about me and not the universe, so to speak (though I would be grateful if you could point out a way to be morally relativist without morally nihilist).

I think that you're confusing moral universalism with moral absolutism and value monism.

The last paragraph of my previous post was a claim that unless you an objective way of ordering conflicting preferences (and I don't see how you can), you are forced to work under value pluralism. I did use this as an argument against moral universalism , though that argument may not be entirely correct. I concede the point.