One of the things that annoys me greatly is how nudity is used, and not used, by Hollywood. Nudity is almost only used for sex. While there are exceptions to this it is rare that you will see nudity for any other reasons. This annoys me because some of my favorite stories would require nudity be used for things other then bringing in the sexy.
The Puppet Masters by Robert Heinlein (Very good book, spoilers for that ahead) is the best example I can think of, you could not faithfully adopt it for TV or a movie if you were unwilling to use a lot of non-sexual nudity.
In the book you aliens invade who can wholly control your body if they are touching any part of your skin. They are flat and about dinner plate size so they can easily hide under clothing. When they are discovered they had been working for months and had already spread through more then a third of the country. They would have taken the entire continental US in a few more months with no real fight.
The only way to stop them required the main characters to convince congress to make wearing clothing a capital offense punishable by death. This was the only way to make sure invaders could not just walk into any city they wanted and start converting people.
That was about as easy to do as you would think, their also was the issue of winter, it was a few months away and they had to win before they would be forced to wear winter clothing.
You should not assume that everyone wears clothing like we do for the same reasons we do.
The first of many reasons for nudity would just be that a people don’t have the same taboos we do. One example of this is in the lensmen series, about half the planets with people like humans don’t have the nudity taboo.
There is nothing wrong with using this, in fact I would use it for sure if there was a huge disincentive to wearing or making clothing for a people. For example if clothing was not needed and a people were on the edge of starvation they would probably not waste time making it.
This also can be a way to show a people are different, it is easily something that could change over the course of a couple generations on a colony.
Under some conditions I would be surprised if this did not happen. For example if everyone on a colony were genetically engineered and always perfectly fit that would remove one big reasons for the taboo. This would be even more likely if we are talking about a people who live on a station or somewhere that weather is not a factor.
Another reason is humiliation, if you want to humble or humiliate someone stripping them bare can help. If your book has a slave class you could have clothing be a way that status is shown. For the same reasons it can be used for interrogation.
Honestly this is one thing that bugs me when I see someone being tortured on TV, this is the first thing you would do. Its not like you would be okay with torture but not okay with stripping someone nude.