Ahhhh the joys of owning a herding breed. I went through this with Winter when I first got her, it was more when I was running with her then trying to walk and there are still times when she attempts to nip me still. Plus there are still times when she will nip at my family members, it's only because of how they react to it.

What I learned with Winter was that when she tried to nip I would ignore her, I wouldn't pay any attention to her, not to tell her to stop or anything like that, I would just ignore her and stand still as could be and look up or anywhere else until she stopped trying to nip me. Of course when I was running with her I couldn't exactly stop because she would try to nip me when we were on course so I would spin and take away the object of nip...does that last bit make sense?

Anyway when you push Chewy down to the ground you're doing what he wants, he wants you to pay attention to him so do just the opposite. I know that it's going to be hard Ash but try to stand still and ignore him when he realizes that him nipping at you isn't actually working and you aren't going and doing what he wants you to do he should stop. Chewy seems like a smart little guy so hopefully it won't take him long to realize that.

The only other thing that I can think of is to get one of those water squirt bottles, fill it with water and squirt him whenever he nips at you...that only works if he hates water and if you don't mind walking around with a water bottle all the time...in other words in can be a complete pain in the butt.

Hope this helps Ash.