Make a pocket. Slice each chicken breast horizontally to create a pocket, being careful not to cut all the way through.
Season and stuff. Season the inside and outside of each breast with salt, pepper, and garlic powder. Tuck a slice of cheddar inside each pocket. Add herbs inside or on top of the cheese if using.
Wrap with bacon. Wrap 2–3 slices of bacon around each stuffed breast so it covers most of the chicken and helps seal the pocket. Secure the ends with toothpicks if needed.
Preheat. Preheat the air fryer to 375°F (190°C) for 3–5 minutes so the chicken starts cooking immediately.
Arrange. Place the bacon-wrapped chicken in the basket in a single layer, not touching, so the air can circulate.
Cook. Air fry for 15–20 minutes, flipping halfway through, until the bacon is crisp and golden. Time varies with breast size and air fryer model.
Check doneness. The chicken is done at an internal temperature of 165°F (74°C) on a meat thermometer. The bacon should be crispy and golden brown.
Rest and serve. Remove the chicken, let it rest a few minutes, take out any toothpicks, and serve hot with your favorite sides.