The chords for the hymn "How Great Thou Art" are generally in the key of A flat. The basic chords for the song are Ab, Db, Eb, Fm, and Bb. Here is a simple chord progression to get you started:
Verse: Ab - Eb - Ab - Eb Ab - Eb - Fm - Bb
Chorus: Eb - Ab - Eb - Ab Eb - Ab - Bb - Fm
Feel free to experiment with different inversions and variations of these chords to create your own unique version of the song. Happy playing!