To begin with, I find that there are two primary beliefs when it comes to nudity. The first belief is that nudity exists only to be provocative, either for shock value or to express implicit sexuality. The second belief is that nudity has artistic or literary value when used well, just like any other tool. If your beliefs are of the former, you can skip this post.
Nudity is a tool that a writer can use to express some quality of their character. What I find interesting about nudity is that it actually has a wide range of uses.
Classically, the naked body is considered a frail thing (especially with women). We people are always "wearing masks", hiding behind badges, or garnering strength from their uniforms. To strip a person of all their armors leaves only all the fear and helplessness behind. The naked body is not fit for being in society, nor is it fit for existing in nature.
In the complete opposite view, the naked body can be considered the most unbridled, pure form of humanity. A person without any of their clothes or any other coverings is not stained by culture or class or belief. Here, nudity is the throwing off of our shackles. Since humanity can be seen as an unstable force, then a character's nudity is a crowning moment when they reach their full power.
And somewhere in the middle, nudity can show laziness or indifference. It's when people don't care about showing off, dressing up, or even dressing at all. It can show a comfortableness in one's own skin that they are willing to let their own skin be their "clothes". It can show a connection with nature, that we are part of the earth and the rest of the animals and not separate with them, like we may think.
Of course, how we actually going about depicting nudity is a whole other story.