I've never heard the High Kings version.

The chords you need depend on the which key you sing it in. And which key you sing it in depends on your voice - how high or low can you go.

In the video, threelegoman is singing it in the key of C. Write his chords down. Then figure out what key you are playing in. Say it's D. Write the notes of the scale out, and change the chords for C to the chord below. (I hope they stay put when I press Submit.)

C D E F G A B C
D E F# G A B C#D

C's change to D's, Am changes to Bm, etc.

Keep in mind that the High Kings could be playing in an unusual key like B flat to accommodate their voices. The song has a big range - an octave plus 3 notes down. Not everybody can sing it.