It Must Have Been The Mistletoe by Barbara Mandrell is in Bb at 98 beats per minute and runs 3:11 across 45 bars. It uses 24 chords — F, Bbmaj7, C7sus, Bb, Cm7, Eb, Gm7, Fmaj7, and a few more. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? It Must Have Been The Mistletoe guitar melody tab.