Is a cross breed chihuahua and pomeranian a good breed of dog as far as training and behavior are concerned?

Well first, such a mix is not a separate "breed" ... it's a mixed breed dog, no different than any other mixed breed. There is no reliable way to predict behavior or trainability of mixed breeds because the individual dog may favor either one or the other of their mix. You can try reading behavior descriptions of both Chihuahuas and pomeranians to give you some idea of what to expect, but even that may not be how the individual dog turns out.