Good Luck! I lived in Taos for 30 years. Ron Petersons in Abq has a few things but not much. He used to sell Black powder but you had to ask.
I've been gone for almost a decade now so things may have changed. I used to get everything I needed from Rendezvous but even that has gotten difficult. I used make a drive to Hobbs every so often and buy powder.
Good Luck!