HW: Chastise's spellID changes depending which chakra state you're in, this causes some things to work improperly in macros. I'm not sure of all the details. But, much like how traps work with the trap launcher, you have to place a copy of HW: Chastise itself somewhere on your hotbars to be able to reference HW:Sanc or HW:Serenity in a macro.
If you're using a bar mod like Bartender, place HW: Chastise on a bar you'll never show (like bar 8) then disable that bar.
Now make your mouseover macro, and reference it to HW: Chastise