Cut the broccoli and chicken into small bite-size pieces. Keep in separate bowls.
Add the cornstarch, salt, pepper, and garlic powder to a gallon-sized storage bag and shake to mix.
Gradually add the chicken to the bag of cornstarch in three batch, shaking the bag after adding each batch.
Spray air fryer basket with cooking spray. Add breaded chicken to air fryer basket or trays and then spray top of chicken with oil.
Air fry at 400° for 12-15 minutes until crispy and golden.While the chicken is cooking, add the broccoli to a microwave-safe bowl with 1 tablespoon of water, cover, and microwave for 3 minutes until slightly tender and bright colored. Drain broccoli and set aside.
In a medium saucepan over medium heat, add the hoisin, honey, ginger, vinegar, and soy sauce. Stir to combine and bring to a boil. Let boil for 1 minute then remove from heat. Set aside.
Add cooked chicken to a mixing bowl with the broccoli. Pour sauce over the chicken mixture and toss gently until chicken and broccoli are fully coated.Garnish with sesame seeds (if using).