In a medium bowl, stir together the mayo, milk, vinegar, parsley, onion powder, garlic powder, thyme, salt, and pepper, and refrigerate. (This recipe will likely make more than you'll use for the two sandwiches)
In a small bowl, combine the salt, pepper, garlic powder, paprika, onion powder, and Italian seasoning. Season both sides of the chicken with half of the spice mixture and set aside.
In a large resealable bag, mix together the flour, baking powder, cornstarch, and the remaining spice mixture. In a medium bowl, beat together the egg, hot sauce, and milk.
Place the chicken in the flour mixture and shake until fully coated. Dip the chicken into the egg mixture, then return to the flour mixture. Transfer the chicken to a plate and allow the chicken to rest for 15 minutes.
Preheat the air fryer to 350 degrees F (170 degrees C). Spray the air fryer with oil, add the chicken, and spray thoroughly with oil. Cook for 10-14 minutes, flipping halfway through and spraying with additional oil. Once done, let rest for 5 minutes. Layer the sandwich together on the buns with the mayo, pickles, chicken, and lettuce. Enjoy!