I can help you with this. First, it has Christmas music, and one of my favorite Christmas tunes to boot:
And while it's not an up front theme, the story revolves around family and the reunion of an estranged mom and dad (John and Holly McClane).
You have Christmas snow as the movie ends. (Symbolically as the stolen bearer bonds snow down from the top of Nakatomi.)
And finally, you have not one but two Christmas miracles. The obvious one as the lone hero defeats the band of terrorist/thieves against all odds. And of course the Christmas miracle that is bestowed upon Hans Gruber as he receives his Christmas wish, the FBI.