Heat 2 cups of water to boiling. Add 3 Tbs of the brine mix and stir to dissolve.
Add a cup of ice to a large resealable container. Pour brine mix over ice and stir to cool.
Pound chicken breast to an even thickness and add to brine.
Add more water until chicken is fully submerged. Cover and let brine in refrigerator for 5-12 hours.
After brining, rinse chicken well and pat dry. Rub chicken with olive oil and season with lemon pepper seasoning and a little salt and pepper. Note that a lot of salt is not necessary because the chicken is already brined.
Preheat air fryer to 380 degrees and set turn reminder.
Add chicken in a single layer and air fry for 14 minutes, turning chicken halfway. Let cool before slicing.