No, he isn't getting power nulled at a range.
Okay, because above when you showed that clip and explained that being 'near' them is bad, it made it seem that the Power Null had a passive aura range, which would completely change the context of the fight.
The point is that he can nullify him once he's touched by the chains, and he can shoot the chains from a distance. Kai's first move with the chains is usually to use them to restrain his opp, so ye
Which would work on Santa if he gets it off, but the Mass Attack is the really big problem here.
This form of Santa has no Power Null resist, he doesn't have the enhanced senses upgrade (later CRT, I swear, I'm just so behind...), Kai is definitely more skilled, and because this franchise can't find a lifting strength feat to save its life has better LS.
But the problem for Kai here is that Santa's opening move, and one of his only possible moves, is very likely throwing out a projectile with a hand wave or thought-based that completely AP stomps Kai, and if its a Mass Attack, its going to explode in an AOE. They're super close range to one another, and Kai has no reason to realize that Santa's in a one-shot range against him. Blocking, side stepping, even a long dodge might not be enough and Kai's going to get totally destroyed by a Mass Attack opening move. Given SBA rules, Santa's got line of sight, wants to win, and doesn't have a lot of options in his base form, he's probably going to do it.
Sure, depending on the opening, the chain might still reach Santa too, but Santa's only getting power nulled by that, if Kai's caught in that opening blast, he's just dead...
Kai's wincon is strong, but to actually make use of it? He needs Santa to only use a normal projectile as his opening move, or Kai needs to completely anticipate that Santa's projectiles will insta-kill him and have the ability to explode in a much larger area and just totally bail from the start of the fight to get out of the blast radius, which at such close range might not be likely? And doesn't make a ton of sense to assume since it seems he doesn't have any sort of enhanced senses or Analytical Analysis to realize that the projectile's basically a bomb.
I think the most logical answer is inconclusive. Santa's opening move will completely determine the flow of the fight. Kai can easily clean up if Santa's opening move isn't good, but if Santa chooses to use the very easy to preform Mass Attack? Kai's probably dead while Santa's just power nulled but still alive.
With that in mind, I feel there's no clear-cut winner, and it's really up to split-chance opening decisions that can go either way. I vote Incon with everything I have here.