First, chop the chicken into large chunks. Then, add them to a bowl and pour in the teriyaki marinade with the cornstarch. Use a spoon or you hand and massage everything together. Cover and allow to sit 15 minutes.
Preheat the air fryer to 400℉.
Next, add in the marinade chicken with at least 1/2 inch of space between each. Cook the chicken for 12-15 minutes and flip at the halfway point. The time will vary based off of how large or small you cut the chicken chunks. Remember, they'll shrink.
After cooking the chicken toss in an additional tablespoon of teriyaki marinade. Garnish with sesame seeds then serve.