Problem is, chording is non-traditional in Irish music, so there really aren't any "right" chords for any given tune, other than, say, "it's in D". Beyond that, it's pretty much up to the accompanist, and very much a matter of personal taste, whether you want to stick to I-IV-V patterns or play substitutions.

To me, that's part of the fun. Start with the basics and experiment from there! Also, most guitarists accompany in DADGAD tuning, which makes chords even more ambiguous.

Cheers,
Michael