Don't bother with nystatin, it contains sugar, and sugar makes thrush worse.
(advice given asuming you are nursing) avoid sweets and dairy, get some gentian violet, let your nipples 'air out' after a feeding and at night as much as possible. Dip a q-tip in the gntian violet and coat your babies entire mouth with it, and then get a NEW q-tip and coat one nipple, then get a NEW q-tip and coat the other nipple. Grapefruit seed extrat works too, but I know that gentian violet is easy to find and works great! Do this for 7 days, but don't need to reapply until it wears off, this stuff is bright purple so you'll knwo if its worn offo r not! It will stain but if you only use a tiny bit it won't get all over. Make sure yo uwear an old shirt and put a bib on your baby.
Also find some acidophilus caplets, break one open, get the powder on your finger and let him suck if off, and you yoruself take two acidophilus twice a day. This is good bacteria, a probiotic, and will help your systme fight off the bad thrush bacteria, and it will pass through you milk to him, and if you give him some of hte powder twice a day to suck off your finger, it will get into his system too and fight off the thrush.