No, I don't think it's possible to recapture his old audience, especially the piece of it that threw money at him hand over fist during the Vic lawsuit and for a long time after. He literally told his old fans to fuck off because they weren't on board with his ever increasing public displays of sexual degeneracy.
If Nick woke up tomorrow and announced he was going to rehab, I still wouldn't watch him again. The magic is gone and all that's left is a two faced lying faggot. But best of luck to him, I hope he makes a million dollars.