He's probably not going to federal prison. I don't support Nick at all. I think he's a child abuser He's (probably) got the FBI looking at him, this will most likely result in a legal headache for him and damage his reputation further, especially if he ends up taking a plea deal. Unless this exposes something else that's worse, like what MIGHT BE on MAPton's harddrive, not much will come out of this beyond maybe paying a fine and a restraining/gag order.
Is he going to become the Prison Bull's bottom in Maximum security prison over this? Probably not. But will this fuck him up, stress him out, which will result in more binge drinking/drug use, which will further result in public meltdowns and potential parole violations? Almost certainly!