One of the great assets of having a player like Nate Robinson is hard to measure in numbers. How do you gauge energy anyway?
You can look at something like net rating, which looks at how much a team outscores their opponents per 100 possessions. The Bulls are a plus-6.8 while Robinson is on the court, compared to a plus-6.1. That doesn't really show anything about energy, though; it just shows they're a little bit better.
What's interesting, though, is that per 48 minutes they are a plus-3.2 while he's on the court compared to plus-8.2 while he's on the bench. Based on that, you might conclude they're a little bit better while he's sitting.
Either way, though, they're better than their opponents, but where I'm going with all this is pace. Why is it that when you look at net rating the Bulls are better when Robinson is on the court, but when you look at per-48-minutes it looks like they're better when he's on the bench?
The answer is energy. When Robinson is on the court, he brings energy and pushes the pace, thereby obscuring the per-48-minutes stats. The quicker pace is how he makes up the difference.
Sometimes the Bulls need that energy, and he's been excellent in that role.