He bit me

[ELubas]

Absolutely take away all of his privileges. Make sure he eats last, never gets anything like a treat or even a pat without making him sit or down first. I think he may have been challenging your status in the pack. It seems his way of saying "I can sit here if I want" and since you moved him, he reacted this way. DO NOT let him back on the couch for any reason for a good long time.

I would have to second this-a part of NILIF is they earn thier priveleges-and sleeping on a comfy couch is a HUGE privelege for a dog. Keep us posted on your progress and good luck with that nail-sounds sore