Dog Obedience Training Recommendations

We recently adopted a rescue and are looking for recommendations for a good dog trainer. Our dog is a one year old mutt that has a habit of nipping when he plays. We've taught him basic things like sit and stay but can't seem to break him of the play biting. I believe it's a carry over from his puppy days and he was just never taught otherwise. I'm sure we could keep working at it but I think a basic obedience class would do him good.