Put one of his beds in the nursery. Start treating him like baby is already here. No jumping on you. On the couch. Sleeping in the bed. Etc.
Dogs are great at adjusting, when I introduced my dog to my baby, it was when. he seemed interested and looked into her bassinet. I sat on the couch and called him over and let him smell her and give her a kiss, make sure that you are calm and that he is calm if he starts to get too worked up and excited tell him to be calm and try again later. I explained to my guy that the baby was his responsibility now and he had to be her protector, I think they understand way more than we give them credit for. good luck