Actually, St. Nicholas day isn't really our Santa Claus,  St. Nicholas day is celebrated on 6 December for Western Christians and 19 December for Eastern Christians (My family puts up our tree up on 6 December to celebrate this day/St. Nicholas.).  "Our" Santa Claus is really a mash-up of "traditions surrounding the historical Saint Nicholas, a fourth-century Greek bishop and gift-giver of Myra, the British figure of Father Christmas, the Dutch figure of Sinterklaas (himself based on Saint Nicholas), the German figure of the Christkind (a fabulized Christ Child [Kris Kringle]), and the holidays of Twelfth Night and Epiphany and their associated figures of the Three Kings (based on the gift-giving Magi of the Nativity) and Befana."

Additionally, some folklorists theorize that all versions of Santa Claus begin with the Germanic pagan god, Wodan and German Christianization.

Full disclosure, I am an agnostic Christian who believes in the teachings of Jesus the Jew.  Merry Christmas"