Sorry Goat2 but I have to disagree. Even with all that good stuff Nick is doing with kids etc, and his much improved on court behaviour, he has very serious personality issues (that can be summarized as "immaturity") so deeply engraved in him, that it's safe to say he won't be able to overcome them. I'm not denigrating Nick and don't want him to stop playing: in the end he brings lots of fun to the game. But I'm saying the moral scrutiny at the top of the game is incompatible with Nick's character, so Nick simply does not belong there. E.g. respect is the bottom line.
This latest incident of disrespectful sloganeering against Verdasco on Twitter, stems from the fact that Verdasco's opponent Kokk, is Nick's best mate. Yeah, he could say that he wished Kokk would win and everybody would agree he should support his friend. But throwing in a denigrating joke about his opponent is a serious mistake.
Remember what Nick muttered to Stan on court, not so long ago? I don't need to recall the details of that disgusting slur on this forum. But note that slur was also a result of the fact that Kokk is the closest friend of Nick and he wanted to contrast his friendship with Kokk against his opponent (Stan) in the fervour of a battle. ATP, like all of us, turned very lenient and imposed just couple months of suspension for this appalling slur, because Nick is young and deserves a chance to come back from it.
Now, let's ask: did Nick learn anything from his mistake therein? Not much because the incident almost repeats itself, in different settings & less serious form but the same social aspect. He clearly regretted his impulse and deleted the offending Tweet. But had he matured since the incident with Stan, he would maybe apologize and say to move over it. But his further engagement and adverse follow-up exchange only aggravate his initial mistake.