Place the chicken breast, buttermilk, and pickle brine in a large ziploc bag or shallow bowl (ensure the chicken is covered as much as possible). If you have time, set the chicken aside to brine for up to 2 hours. If you're in a hurry, just let the chicken brine while you prepare the other ingredients.

Add the flour to a shallow bowl and season it with a pinch of kosher salt and cracked black pepper.

In another shallow bowl, beat the egg with 2 tablespoons of the buttermilk-pickle brine mixture.

In a third bowl, add the breadcrumbs and season them with a pinch of kosher salt and cracked black pepper.

Preheat your air fryer to 400°F/200°C for 5 minutes.

Remove the chicken breasts from the brine and allow any excess brine to drip off. Then dip the chicken breasts in the flour, making sure they are evenly coated on all sides.

Next dip the chicken breast into the egg mixture and finally into the breadcrumbs.

Carefully grease your air fryer basket with olive oil spray and then place the breaded chicken breast into the air fryer. Spray the chicken lightly with olive oil spray.

Cook at 380°F/190°C for 15 minutes. Then flip the chicken and cook for an additional 8-10 minutes, or until golden brown and the internal temperature reaches 165°F/74°C.

(Optional) To toast your buns in the air fryer, spray the cut side lightly with olive oil spray and place them cut side up in your air fryer basket. Cook at 400°F/200°C for 2-3 minutes, or until your desired doneness.

Place the crispy chicken breast on a toasted bun and add your desired toppings. Enjoy immediately.