SoundofJoy did an excellent tutorial on this song a while back, I believe it was in the key of C...
Here are some alternate chords in Ab
(Basic)
-/C,C,Db,Eb,Eb - I JUST WANT TO PRAISE
Ab/G-Bb-C-Eb YOU
Ab/G-Bb-C-Eb
Ab/G-Bb-C-Eb
/Eb, /Ab - FOR EVER
Eb-Eb/Db-Gb-Bb
Eb-Eb/Db-Gb-Bb
Ab-Eb-Gb/C-F-Gb-Bb
/Eb, /Ab - AND EVER
Db-Db/C-Eb-F-Ab
Db-Db/C-Eb-F-Ab
Db-Db/C-Eb-F-Ab
/Eb - AND
Gb/E-Ab-Bb-Eb, /Db - EVER
E/Bb-E-Ab, /Bb - FOR
Eb/Eb-Ab-C - ALL
Eb/Eb-Ab-C
Eb/Eb-Ab-C
Eb/Eb-Ab-C
/Ab, /C - YOU'VE DONE
D-D/D-F-Ab
D-D/D-F-Ab
D-D/D-F-Ab
/C, /Bb - FOR ME
Eb-Eb/Db-F-Ab
Eb-Eb/Db-F-Ab
Eb-Eb/Db-F-Ab
G-G/Bb-Db-Eb-G
G-G/Bb-Db-Eb-G
-/C,Db,Eb,Eb - BLESSINGS AND GLO-
Ab/G-Bb-C-Eb - RY
Ab/G-Bb-C-Eb
Ab/G-Bb-C-Eb
/Eb, /Ab - AND HONOR
Eb-Eb/Bb-Db-F-Ab
Eb-Eb/Bb-Db-F-Ab
D-D/C-D-E-Ab
/Eb, Db/C-Eb-F-Ab - THEY ALL
/Eb, /Eb, /Eb - BELONG TO
Gb/E-Ab-Bb-Eb, /Db - YOU
E/Bb-E-Ab, /Bb - THANK YOU
Eb/Eb-Ab-C - JE-
F/Ab C Eb - SUS
-/Ab FOR
Eb/Bb Eb G BLE-
F/C F Ab E-
G/Eb G Bb E-
-/C, Bb,Ab SING ME
Db/Db F Ab
C/C Eb Ab
Bb/Bb Db Eb Ab
Ab/Ab C Eb Ab