Santa can be okay in this sort of deck, but it can be tough to use effectively as you don't play with enough lower-cost cards to keep your hand size below your opponent's - often leaving to Santa being more beneficial to them than you.

Secondly, about TO in Nish. I tried it for a while as the only ally in my "ally-less" Nish. What I found out is that you're paying (4) for a 2/2 ally that's going to net you a card gain of 1, if you're thinking of it in terms of an ally that you can play and then "safely" blow up the board. In the end, very low damage output for a minor card gain, at cost (4). Not that TO isn't a great card; just not in this kind of deck.