Now, he's no Saint and did some bad things. He just had a massive inferiorty complex. But he showed some deepness. His Zanpakuto is "Sacred Grieving Mantis." So, he's grieving for something. Then he talks about how his race is damned regardless and will never have a chance at redemption. This seems to show, he doesn't revel in being what he is. But since he is what he is, he wants to be respected and recognized as a strong warrior of that kind. As oposed to being stuck as something pathetic, then dying a pitifully death w/o so much as leaving any kind of impact that he even existed at all.
He was sadistic with Nel, but it seems out of revenge if anything. He feels she never respected him, looked down on him, and was just a jerk to him in general. But since she had more experience over him on the battle field, he could never best her. Now that he's gotten stronger, he wants to give her her turn on the recieving end of being "weak" and tormented. Nnoitra only had one Fraccion, but he was shown to care for the one he had. Now, he wasn't buddy-buddy and kissy kissy with his Fraccion, but all in all, Nnoitra actually allows Tesla to travel with him and really talks to Tesla. Then when Zaraki got after him, Nnoitra screams for him to run away. And the databook stated Nnoitra grieved for Tesla. It read "Nnoitra's shaken grief is interrupted by Zaraki's call of "Next