Nipping can be a greeting, sign of affection/excitement to a pack member. Both my Bull X bitch and my Malinois dog do it and sometimes my Terrier/Spaniel.
But here we go with the "hole in the ground" and the "PTS pose" or should I say "No nothing" and the "couldn't be arsed pose"
I'd make something of that dog, but hey ho, I don't need it.
Good luck with finding a new home, looks a nice dog.
Forgot to add, if you can't find a decent home, give it to one of the PTS pose, they'll sort it out .