Place leftover chicken breasts in the air fryer basket in a single layer without overlapping each other.
Air fry for about 5 minutes until warmed thoroughly or until an internal read meat thermometer inserted into the center of the chicken breast reads 165 degrees F.
Notes
Reheating time depends on the size of your chicken breasts and type of air fryer you own. Small basket air fryer reheats food faster than large basket one (the one you can fit 3-4 breasts in, in a single layer). Here is a general guideline: