Nick really looked disgusted by Kaitlyn
The first thing he said to her on Jimmy Kimmel was "thank you for not picking me." Both Kaitlyn and Andi responded, but he seemed to be pointing it more at Kaitlyn. He also said in an interview that Andi is a great young lady and he's glad she picked Josh, and he's even more happy that Kaitlyn picked Shawn. Lol ouch.
Also, when Kaitlyn was going on and on to Jimmy Kimmel about how she was happily engaged and Joel McHale sucks and just carrying on so that no one else could get a word in edgewise, the way Nick was looking at her spoke volumes. She was laughing uproariously, and he was just looking at her and not laughing at all. He was just looking at her with a blank stare as if he didn't even know what he had ever seen in her.
I think he's glad he dodged that bullet. Lol.