Once Upon A Christmas by Dolly Parton is in Am at 66 beats per minute and runs 3:10 across 24 bars. It uses 6 chords — Am, G, D, C, E, Em. 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? Once Upon A Christmas guitar melody tab.