I was prescribed Fluconazole 200mg (which is the drug found in Diflucan) for two weeks by my doctor and that was enough to clear up my esophageal Candida infection. I didn't have any side effects from the medication, but that's just me. I did have die-off effects the first week, but those slowly subsided and I was up to 100% towards the end of the treatment.
I've never taken Nyastatin, so I can't offer any personal experience there. Just ask some others who have taken it to get feedback from them.