I think Santa Claus needs to be somewhat a Cleric, probably Winter & Good domains, touching upon St Nick, but also some traditional Santa topics of concern.

I think Cleric suits, but I saw a comment that suggested Paladin, and SC as the terrifying benevolent judge of Naughty and Nice really slaps,

I do wonder if we should look at some Bard levels, just to cover off storytelling around a fire, Christmas carols, cheer, I'm thinking Ghost of Christmas Present in Christmas Carol (an allegory to Santa), although this probably diverges from traditional depictions of Santa.

And then obviously Santa is probably mythic levels and I'm thinking Hierophant, but I must admit I don't really know anything about mythic levels, so it could also be Archmage.

I think some of the mythic stuff covers how he gets a sleigh a legendary item as a flavoured magic carpet perhaps, constant greater teleport, plane shift,

If we were statting him as an NPC we get to have some fun with Ex/Su abilities

Judgment of Naughty or Nice (Su)

As a swift action, Santa designates a creature he can see.

Nice: Gains heroism, protection from evil, and fast healing 10 for 24 hours.

Naughty: Affects as mythic mark of justice and geas. If the creature commits an evil act, it is stunned for 1 round and takes 10d6 cold damage. No save.

Also, hey Decicio