Sprinkle some salt on the chicken drumsticks then rinse the salt off using warm water. Pat the chicken drumsticks dry using paper towel.
Add the fish sauce and brown sugar in a bowl to make a marinade.
Pour the marinade over the chicken drumsticks and let it marinade for 15 minutes.
When the 15 minutes is up, place the air crisp rack in the Ninja Foodi 10-in-1 pressure cooker and add ½ cup of water to the bottom of the air crisp rack.
Then place the chicken drumsticks on the air crisp rack in the Ninja Foodi 10-in-1 pressure cooker.
Using the pressure cooker lid to close the pot. Set it to "pressure cook" on "Hi" for 6 minutes.
After the 6 minutes, carefully vent then open the lid. Replace the pressure cooker lid with the air frying lid and set the Ninja Foodi 10-in-1 pot to "air crisp" at 390F for 25 minutes. Half way through the cooking time, carefully open the lid and turn the drumsticks over. This will help them brown evenly.