PB Tangs are one of those insert and hope fish... Some do very well from the beginning, others struggle before settling in, while some just never do well and eventually pass on.
I agree that a Naso might bully for a time, depending on size, but a healthy PB will quickly establish a dominate position in that tank. If you can get a happy and healthy fish you shouldn't have a problem assuming it survives the initial introduction. That is always the trick with PB's though.
I would buy one that has been in captivity for several weeks or months first, eating well, fat belly and is in a tank with other fish. Then after QT, introduce it right before lights out. Keep an eye on it, feed the tank well offering nori etc in more than one location and let the work it out.