Sounds like a typical Heeler. They're high energy, highly intelligent, extremely driven and they need CONSTANT and CONSISTENT reinforcement until they're "trained". Most people don't have the patience or inclination for a Heeler but have them because they're really "cool" dogs. They also need constant stimulation.

The ex had one. That dog pretty much dominated her. Her idea of training was screaming at him. It was great fun for him because there was never any negative consequences to his behavior. With me, I could just look at him and he'd become submissive and calm...because he knew negative consequences were real.

They're really good dogs for someone who likes dogs a lot and for someone who doesn't mind working with them a bit. It doesn't take a lot of effort...just consistency. They really respond well to positive reinforcement because they're so driven. And they're extremely loyal...pretty much a one person dog from what I've seen.

The nipping thing is very common to that breed...they're a herding dog and that's just what they do until they know they shouldn't.