The Nightmare Before Christmas sits somewhere between Halloween movie, Christmas movie and cult classic. Personally I lead towards characterising it as a Halloween film because I feel it works better in this context: at Halloween, when everyone is invested in ghosts, ghouls and things that go bump in the night, it's the story of some cute monsters trying to do Christmas and getting it hilariously wrong. At Christmas, when everyone's feeling festive it's more like the story of the Grinch except with misplaced enthusiasm as a motivation instead of greed. Since there's a limit to the number of times you can watch the same basic plot in one holiday, I recommend keeping The Grinch (the original animated one for preference) for Christmas and saving the skeletons for Halloween.