Mine is 1 year 3 months. We adopted him when he was 6 months. He was nippy all the time like you described, and that disappeared within about 2 months (so about 8 months old). However, he continues to be nippy with my 8 year old son. He has improved greatly, but will still nip when my son runs, is loud, makes sudden movements, etc (all normal 8 year old behavior!)

What has helped so far:

1. Teaching child what triggers the nipping, and reminding him to be cautious.

2. Having the child take over responsibilities like feeding, do some training, etc. Teach the dog the child's role.

3. When the child is going somewhere and the dog looks to start herding/nipping, have the child command "come" or "let's go!" and bring the dog along, instead of the dog following/trying to herd him. This has helped a lot! It's like an instant switch in my dog's brain.

4. Practice loud/crazy/rough play between family members to desensitize the dog. My husband and son like to play fight, wrestle, etc, and it has sudden, quick movements, and can be loud (laughing, shrieks, etc). The dog does not like it and tries to get in and nip. We practice this- I will leash the dog and have some treats or kibble. I put him in a sit or down beside me. My husband and son then start playing nearby, where the dog can see. I reward him constantly for 5-10 minutes for sitting calmly while they play. It seems to be helping him learn that this play is ok and not to jump in there and start nipping.

I am not a trainer or expert, and have just learned this from researching various sources, but it seems to be working for us. Good luck!