@Garrett **********
In Chiang mai you need a minimum of 21 days left on your current stamp to apply for the in country Non-Imm visa because it goes under review for 20 days before you go back and get the Non-O visa and new 90 day stamp inked in
@John ******
you don't have enough time on your current stamp to apply SO go apply for a 60 day covid extension again before this stamp expires and THEN you will have the time needed to apply for the in country Non-O at the Chiang Mai immigration office