I took nystatin for 10 years and it's only good for one thing: if you are deathly sick and can't get out of bed, then take it. If you have no hope and other anti-fungals have failed. Nothing else.
Taking nystatin, sure some of my symptoms stopped, but I was slowly dying the last 10 years. Almost completely unable to exercise the last 3 years. My liver was heavily damaged to the point where I was very ill. And then the candida became immune to it.
No, I can't say I recommend it for long term use. It's a drug and all drugs are toxic and harmful. Sure, my colitis went away but that was replaced with pneumonia and broncitis. I got that to go away and then my liver took the brunt of the damage and I was getting eaten alive by different infections and bacteria.
So do whatever you want, just realize that's it's not a big loss. There are several other (better long term) solutions out there imo.