I would just use the Nystatin until you run out. Then use the Medistatin, or get the Monistat/Miconazole. Medistatin can be mixed in water and given with a syringe, or mixed in water or food. Monistat is what azygous uses in her article...
The dosage is 200,000 to 300,000 units per kilogram (each 2.2 pounds,) every 8-12 hours. So, you could give her 1 tablet twice a day. That would treat an an 4.4 pound chicken. About how much does she weigh? You can get Medistatin (Nystatin for birds online, and dosage is on the package) which...