The nose is the most sensitive part of your dog. Smacking the nose will just increase the biting. If you ever tune into Cesar Milan (dog whisperer) he never smacks. It's not a natural form of punishment for the dog. He says that when puppies are disciplined by their mummy dog she will give a gentle bite in the neck area. He recommends you use two fingers to quickly give a firm touch there to imitate what the mother dog will do. If you go on his website you can read about it. Smacking a dog?? No I don't think so. Also remember your dog is a puppy... You need to train now and they chew and bite. I do the quick touch on the neck with my dog and she responds and doesn't continue. Check out some of the episodes online or something. He's very informative about what to do with your dog.