Fully automated outputs (like pulling an image at random from thispersondoesnotexist.com) would be public domain since non-humans cannot hold copyrights and no creativity was applied.
This is analogous to the "creativity" of a photo being the settings and framing done by the person who set up the shot and is why the famous "monkey selfie" fell under public domain[1].
[1] https://en.wikipedia.org/wiki/Monkey_selfie_copyright_disput...
https://news.ycombinator.com/item?id=27635481
I think Monkey selfie copyright issue was subtly different.
I do think you should always be the copyright owner, unless it's clearly stated in their terms that any image created using their tool is owned by nVidia.
"Hey pen, sign this contract."...
This same question often comes up with self-driving cars and "fault", and it seems to regress into the same trap. Ownership of _risk_ is one of the primary concerns of capitalism. The question is not, "who should be at fault?", it is instead "what is the cost of this risk?" and then we buy and sell that risk like everything else (which is also how we determine that cost). If the self-driving advocates are right and self-driving is safer, then the risk will likely cost less than your current insurance.
Of course, it's not always clear. If the parties can't agree who owns a thing, they often use some legal mechanism to resolve their dispute.
Because actually the user isn't. The AI is. AI's don't have a right to copyright. You making a few lines and the AI making the actual image does not make you the creator of the image.
For algorithmic art, likewise the developers of the software typically provide permissive licenses to the users of the software.
AI makes this harder because the works are massively derivative works, which AFAIK, do not have much precedants in law. The question is not easy to answer unless the author (Nvidia in this case) owned copyright over all training data.
Good artists copy, great artists steal.
AI does both :D