Make the stuffing: to a mixing bowl, add cream cheese, finely chopped jalapeno, mozzarella, garlic granules, onion granules, cajun seasoning and mix to combine then set aside.
Make a pocket in the chicken breast: To make a pocket in the boneless chicken breast, pat the chicken dry with a kitchen paper towel. Then place the chicken breast smooth side of the breast up on a cutting board.
Working on one chicken piece at a time, place one hand flat firmly on the chicken to secure it then with a sharp knife cut horizontally through the middle but stopping before you cut all the way through. (It should look like a butterfly or an opened book at this point) Be careful not to cut through the top, bottom, or opposite side.
Stuff the chicken: divide the filling equally and stuff the chicken breast with the cream cheese filling.
Seal the chicken with toothpicks to help secure the filling. That said, it would still ooze out during cooking but that is totally fine.
Season the chicken: Brush the stuffed chicken with oil on both sides then season with salt, black pepper, and the remaining cajun seasoning.
Line the air fryer basket with aluminum foil then arrange the stuffed chicken in a single layer in the basket smooth side down.
Air fry for 18- 20 minutes until the internal temperature registers 165F/74C. Flipping the chicken halfway through cooking time.
Remove the chicken from the air fryer to a plate. rest for 5 minutes before slicing or serving it. Enjoy!