Welcome to YorkieTalk
What a cutie pie! I could just eat him alive with kisses.
The nipping is perfectly normal puppy behavior and will go away as he matures. Thre are several ways to help discourage the "too hard nipping. Here are my two favorites. I am sure you will get lots of ideas.
1) Tell him NO in a firm voice and stop playing and ignore him completely for about 5 minutes (any longer he wouldn't understand)
2) Fill a spray bottle with water and spritz him when you say NO
It looks like there is some serious love going on there --
