We cooked the chicken in a 3.4 qt. Air Fryer. For that size of air fryer, 2-3 chicken breasts is about the max without overcrowding the air fryer. If you have larger size, you can probably cook 2-3 more so long as they are still in a single layer. Adjust cooking time for thicker or thinner chicken. Some brands of Air Fryers will cook slower or faster than others, adjust accordingly.
If needed, pat the chicken dry. Cut the chicken breasts in half, lengthwise. Pound the chicken breasts into thinner pieces. Season with salt and pepper.
Air Fry at 360°F for about 6-8 minutes. Flip the chicken breasts and top the chicken with marinara sauce and mozzarella cheese. Air fry for another 3 minutes.