It didn't get called because the way Nixon reacted keeping his cool. But you can tell Nixon didn't appreciate it. Seemed like an unnatural movement to me even in real time speed. And yeah the way he didn't turn around until he was all the way down the court...that body language told me that he didn't want to look at the ref or Nixon because he wanted to get away with it. People that do something wrong never want to make eye contact because they are afraid that their face will reveal that they know they did something wrong.