Will nudity be against the law?
Not against any of our rules. Whether player civilizations decide to outlaw nudity is up to them.
I'm pretty sure any asexual creatures will find clothing to be pointless to wear...
Oh, so the only purpose of clothing is to hide your naughty bits, now? Nah, asexual beings would still have uses for Art (any developed species would), Protection/Shelter (from the elements, or even wearing armor), or even to designate ranks or the like, as clothing.