Place chicken in a deep container or gallon zip-top bag and pour pickle brine over to immerse. Refrigerate for at least 2 hours.
Preheat air fryer to 400ºF.
Remove chicken from brine, pat dry thoroughly with paper towels, and cut into 1-inch pieces.
Set up breading stations with flour, beaten eggs, and seasoned breadcrumbs mixed with onion powder, garlic powder, paprika, and sea salt.
Coat chicken pieces by tossing in flour, then egg, then breadcrumbs.
Spritz air fryer basket with non-stick cooking oil spray.
Place nuggets in basket without overcrowding, spritz the tops with cooking oil.
Air fry for 6 minutes, flip halfway through. Check internal temperature; continue in 2-minute increments until 160-165ºF.
Carefully transfer cooked nuggets to a plate.
Repeat cooking until all nuggets are done.
