@pointythings
This is the bit I have never heard any atheist I know say. So I don't know any atheists who have accepted that particular form of moral nihilism.
Well for example, Sam Harris did a book denying free will.
Now to be clear, Sam Harris wouldn't claim to be a moral nihilist. Harris also did a book arguing his own moral perspective.
But Harris is saying that rapists and murderers, when it really comes down to it, are completely innocent.
Again to be clear, he isn't saying you can't lock them up as a deterrent or for public safety. You can treat them as "guilty" under normal legal standards presumably.
However without free will, they aren't ultimately to blame for their actions.
So that would be an explicit denial of moral responsibility, and I would think it would destroy the idea of moral duty also.
So yes, this well known atheist is guilty of a form of moral nihilism.
Another example would be Daniel Dennett, who defends free will but a compatibilist version of it. Dennett isn't actually claiming that people are more morally responsible than Sam Harris thinks. So same issue.
I don't know any "big name" atheists that are taking an alternative approach. I'm sure there are some lesser known writers, but not the big names in atheism.