How old is he ? He could just be going through a stage of preference, where he is moody but knows better than to bite mommy ! When we rescued Athena at 6mo old, she was from an abusive home and was in her puberty stage. So she was attacking everything. She still nips at my hubby on occasion, but if she starts to bite or spray at me, I point a finger at her and say no and she barks at me and calms down. You may just have to find something like that that settles him down. Chins are very untrusting and even if someone slightly squeezes them too hard once, they remember and just won't have anything to do with them (how she acts with a friend now, because of this).