This is one of the sub-species of Mycobacteria avium (over 100 different ones have been identified in humans to date.) As far as I can tell, it is treated with the 3 antibiotic regimen just like most of the others.
Here is an article addressing it:
https://clinicalproteomicsjournal.biomedcentral.com/articles/10.1186/s12014-019-9260-2
If your pulmonologist is not experienced in treating MAC/MAH, has she talked about referring you to someone else, or adding and Infectious Disease Doc to you care team?
Sue