I didn't say this year, I said as a player. Nurse's defense was a pretty big factor in Edmonton losing the cup last year and it's been multiple years where he's been inconsistent at best. I don't think Kesselring is better now than Nurse was at his peak, but I do think he's a better player at the moment- if Nurse continues to play like he has and Kesselring doesn't continue to improve by Leaps and bounds it's a lot closer. It's close in general anyways. I wouldn't bet on Kesselring continuing to improve but I also wouldn't bet on Nurse continuing to play like he has for 3-5 more years. That makes Kesselring more valuable due to age and contract.
And Kesselrings prime is just happening now, how long it lasts no one knows but there's a good chance that it could last for 8 years as that's usually when D-men start declining and Kesselring is big and doesn't play a style of game that will deteriorate or that relies on skating. Kesselring isn't a mid level NHL player at this point. Whether he stays on Utah or not IDK, but on many teams he'd be a top 4 d-man and arguably should be on Utah, and he has the chance to push to be a #1D-man on other teams or potentially Utah.