Cut the chicken into cubed chunks, then toss in a bowl with the starch. Use enough to coat the chicken evenly.
Place in the Air Fryer and cook according to the Air Fryer Manual for chicken. (Ours is cooked on 390°F for 25 minutes.)
Halfway through the cook time, turn the chicken.
While the chicken is cooking, in a small saucepan, combine the garlic, pineapple chunks with the juice, pepper, onion, water, sugar, vinegar, and the soy sauce.
Whisk in the ketchup and let it get to a nice, low boil.
Whisk in the cornstarch and continue cooking for about 5 minutes until it’s thickened.
Remove the chicken from the Air Fryer and then add the sauce and coat the chicken with it.