Weird that you think he’s going around nude at home “at you” somehow. If that’s true, he needs to gtfo.
I would just say, “hey Josh, you share this house with other people. You need to have clothes on. Go get dressed.” If he refuses, then tell him that’s unacceptable and he needs to find his own place. Give him 3 months to find a place and move out if he won’t follow the house rules.