Tripp had no intention of ever taking into consideration Nick's opinion of who should run the company. He recognizes that most of his children are incapable of leading his empire. Brian is the only child with enough loyalty and experience to lead but Tripp still resents him because Leticia lied about his paternity. It was a no-win situation for all of them, but Tripp still wanted the joy of seeing them shocked by his ultimate decision.
Tripp placed Nick in charge of the day to day operations of Darling Enterprises but he was also placing Nick under his thumb. Tripp is a man who wants control of everything around him and Nick is no exception. The episode references The Godfather with the closing shot. Nick is being brought into the Darling fold while Lisa looks on helplessly. Nick may be doing it as means of getting dirt on Tripp, but he is in way over his head.
The second came when Brian and Nick had a rare bonding moment in a jail cell. The two both recognized Tripp as their father's likely murderer and both also realized they are powerless to do anything about it. It was a quiet moment, one that I hope the show can continue to incorporate despite the fact that producers have suggested that it might go in a more soap-y direction in an effort to generate more solid ratings.
Brian Moment of the Episode:
Brian gets into an fight with a chubby police officer and says, "Bring it, doughnut hole."

I'm glad you quoted Brian on the "Bring it doughnut hole" line. That was an instant DSM classic for sure. This show is still on track after the long break. Can't wait for oct, 22. Is there anywhere I can find a sneak peek?
DSM used Atlanta's own Black Lips' "Veni Vidi VIci" on S2-E1 recently. great show besides that as well