Nick's return to the UFC was very, uh, Diaz.
Leaving Strikeforce on the Daley win with as much enthusiasm and momentum around him as he'd ever had, he was lined up to fight Georges St-Pierre for the UFC welterweight title.
Except, because Diaz is gonna be Diaz, he skipped a press conference and got pulled from the title shot. A bunch of crazy talk and card shuffling resulted in him fighting BJ Penn on the card and then lining up with Carlos Condit a few months later thanks to a GSP knee injury.
Condit won, prompting Diaz to hit the sport with the first retirement/suspension perhaps in its history. He retired in the cage, citing terrible judging as his reason, and then later was suspended, citing love of marijuana for the reason.
His retirement/suspension ended at UFC 158, when he finally got the St-Pierre fight and suffered a dreadfully uninspiring decision loss to the champion. He did, however, push the pay-per-view near a million buys with his willingness to say anything that came into his head, from imagery of friends being shot on the streets of Stockton to GSP being "pampered up" thanks to his millions of dollars.
It was an insane 18 months or so, capped off by one of the most remarkable pieces of fight promotion that MMA has ever seen, especially for a fight that almost no one thought was either deserved or likely to be competitive.
Diaz retired again after that fight, presumably thanks to the Scrooge McDuck vault of money it made him. He's recently admitted he'd come back for the right price and the right opponent, putting him in a semi-retired purgatory and leaving his fans to eagerly anticipate his return.