As a child, I recall the only instance that had any major dealing with St. Nicholas, or Swiety Mikolaj, as this is a Polish story.
I believe there was a to-do at our Polish Hall that reflected in some ways La Pastorela. I do recall angels and demons. Then Sw.M. would show up on stage, and all the children would go up and receive a HUGE bag of nuts and assorted goodies. St. Nicholas always remained as part of the Christmas pastiche but he never overshadowed Christ and His Blessed Mother. I do recall as well along the lines of St. Nicholas giving small gifts as the birth of Christ was (and is!) the GIFT at Christmas.
I did get my picture taken with Santa Claus in my early years. In those days, you would never see any Christmas decorations or Santa castle/sleigh until late November or early December. Twere magical days indeed, in the sense that I could palpably sense the spirit (the grace of the holy season) of the Yuletide. The Twelve Days of Christmas, beginning with the Polish Christmas Eve celebration, were truly perceived as a different space in time.
I never married thus no kids and Santa is but a large candle who is not prominently placed, although visible. I do believe we have a Father Christmas figure that belonged to my mother - a gift given to her. Santa is a non-persona amongst some of the children I know from our neosspx mission.
As for the other side or part thereof of the mythos accuмulated around St. Nicholas, I do know we were taught the various European traditions surrounding him and Christmas in my primary/elementary days, so I was aware of Black Peter. I only heard of Krampus when I taught at a Society school. I ended up being St. Nicholas that year, with one of my high school students being Krampus, although no where at overt in costume as that particular figure is portrayed.