Why do they call Santa Claus St Nick?
user
That’s a great question.  For a long time it was just tradition, and now it’s part of the canon that St Nick is the proper name of Santa Claus.  That is, Santa is often called Saint Nicholas, St Nicholas, St. Nick, Father Christmas, or Kris Kringle.  In fact, at one point Kris Kringle was Santa’s actual name, but it’s not used very much anymore.  But it is so interesting that even though Santa is real, his name is actually a figure from legend, and the most famous figure in the legend is Nicholas, a bishop from Turkey.
assistant
Why do they call Santa Claus St Nick?
user
That’s because “Santa Claus” comes from the Dutch word Sinterklaas, which was the name of a “fictitious” Saint who was the subject of many old stories. In these stories, Sinterklaas was often accompanied by his assistant, Black Pete. The Dutch children expected gifts from both men, though many legends say that Sinterklaas came through the chimney, while Black Pete knocked on the door. This would explain why St. Nick and his sidekick have such drastically different names!
assistant
Why do they call Santa Claus St Nick?