I usually try not to repeat myself, but much of this post is a copy.
First of all, there are lots of things you can do except wait. And some of them may slow the progress of the infection in your lungs enough so you "watch and wait" indefinitely without antibiotics. That is not a promise, only a possibility - each of us is different.
I was on the Big 3 for a year and a half, treating and tolerating the side effects as long as I could, before I told my ID and pulmonologist I couldn't do it any longer, even though I was still positive for MAC. They did a CT, which showed improvement,
but not complete clearance, and reached out to National Jewish Health to consult.

In December 2019, I went off the meds, and onto the following routine:
Airway clearance - nebulized 7% saline solution (7% has been shown to also fight the growth of MAC, but lower concentrations can also help thin the mucus & "tickle" your lungs to move mucus) followed by coughing, using my Aerobika if needed. At first twice a day, now once a day unless congested or having asthma problems (then I add levalbuterol neb too)
Anti-mucolytics - the best known is guaifenesin - Mucinex 600 LA (without a decongestant) is what I have been using for 35 years. Recent research in Cystic Fibrosis had also shown that N acetyl cysteine (NAC) is useful to thin mucus, so I also use 600mg twice a day.
Liquid - lots of it, especially water. I also drink and herbal tea called Breathe Easy by Traditional Medicinals, especially in cooll weather.
Healthy diet, moderate exercise and rest.

I have had only one exacerbation that was treated with increased nebs & steroids. My CT scan at 18 month showed no changes. Two weeks ago we caught a bronchial virus and I didn't even get bronchitis - a first for me in over 20 years, so I guess my routine is working.

Do you have an airway clearance routine? With bronchiectasis, asthma or COPD, our lungs don't clear mucus properly, providing a breeding ground for bacteria. So even when we don't feel congested, we need to clear it out ourselves. As I write this, I am sitting here "puffin' the pipe" and coughing!

Sue