Please spell CHU² exactly how it is... If you don't know how to get the ² symbol, then just refrain from calling me CHU² entirely. If you naturally type all lowercase, then chu² is acceptable enough.
WRONG
✘ ⠀ Chu²
✘ ⠀ Chu2
✘ ⠀ CHU2
✘ ⠀ chu2
OKAY
✔ ⠀ CHU²
✔ ⠀ chu²