I've received pictures of these types of "painted nudes" from people who usually send me stuff like jokes, prayer-miracle-nonsense-shit, and cool things that I have never seen before. I had to look a few times and say, "Shit, it's hard to tell that it's some kind of paint!"
I was under the impression that you were doing some sort of casual survey, so I was giving my two cents to draw from.
I brought in the idea of only two choices to help me draw some lines because it is a tough one to think about.
Can I come up with a scenario where I would refer to your painted nude person as something other than nude? Let me explore my thoughts:
First of all, I would never describe your painted nude person to someone who has never seen one as simply "nude". It is just too bizarre for me not to mention the paint.
If we were stuck on an island with only totally nude people and painted nude people, I could see myself eventually referring to the totally nude as "nude" and the painted nude as "painted".
If we were stuck on an island with only painted nude people and clothed people, I could see myself eventually referring to the painted nude people as simply "nude", but I would never describe them as simply "nude".
Like I said, there are some significantly gray areas.
EDIT: I spelled one "eventually" as "entually".