Cut chicken breast in half, creating 4 smaller pieces. Use a meat mallet to pound them to 1/2-inch thickness.

Place the chicken in a large glass bowl, then add ½ cup of milk and the pickle juice.

Toss the chicken in the bowl and make sure each piece is covered in the liquid, then place the bowl in the refrigerator and marinate it for at least 30 minutes, up to 2 hours.

Drain well through a finer mesh sieve.

In a wide, shallow bowl, whisk the egg with the remaining milk.

In a second bowl, combine the flour, salt, paprika, pepper, garlic powder, and cayenne. 

Dredge the chicken, one piece at a time, through the flour mixture, then through the egg, then back through the flour until it is well coated.

Set the chicken aside on a baking sheet for about 15 minutes, allowing the flour to set.

Place the chicken in a single layer inside the basket.

Spray the top of the chicken with the cooking oil spray.

Air fry for 15 minutes at 400F, then carefully flip the chicken and continue cooking it for 6-8 more minutes, until golden brown and crispy and 165F inside.