Merry Yuletide! Io Saturnalia! You see, I knew that Christmas was always a pagan festival, based on the Celtic and Roman ones I just mentioned. The biggest irony is that we celebrate a traditional Midwinter festival, here, with fake snow and pine trees and in blazing summer heat, often with a swim after Christmas dinner.
Santa Claus is from St Nicholas, a Christian bishop, and also Santa is the Spanish for saint. And you add to your cluelessness by bringing in the Nimrod story. He is only mentioned in the Bible, but Tammuz was a real Mesopotamian god with a spring festival, and his “wife” Semiramis was really Sammu-Ramat, an actual Assyrian queen who ruled as a regent, and has been much vilified by Alexander Hislop and Jack Chick.
https://www.worldhistory.org/Semiramis/