If I'd seen Vero in your window, my consciousness would be raised enough to be alert as a neighbour. A precedent has been set! I suspect your neighbour was trying to subtly say he'd noticed but had no objection.
With that assumption, I suspect there won't be any complaints, so perhaps it's only your comfort level that determines how you behave.
I can only imagine that is I was in your circumstance, with my neighbours, I'd be getting direct feedback!
I think, if your neighbor saw you naked and did not complain, you may be good to continue. Ask him to come and visit. He may be a nudist also. If his curtains are always closed, there is also no issue.
In Texas, the law has determined someone who sees you naked through your window has the right to look away. Case dismissed. Only explicit sex displays are illegal.
I am not sure what the established law is here in Wisconsin yet. I think it has something to do with one's reasonable expectation of privacy. I expect that you standing in a window means you should not expect privacy and so are exposed. On the other hand, it still takes a complaint to start an issue. The officer might just suggest you don't stand in the window. He might suggest to the complaint that he keep his curtains closed. No big deal.
The bigger issue seems to be with children. Juries tend to see naked men as perverts and naked women as prostitutes. On the other hand, if there is a complaint, the officer is likely to inform you that you can be seen from the street and you should take appropriate action. It will never be heard by a jury.