Season the chicken pieces with salt and pepper.
Dip the chicken in the beaten egg, then coat with cornstarch.
Preheat your air fryer to 380°F (193°C).
Spray the air fryer basket with cooking spray or lightly brush it with oil.
Place the chicken pieces in the basket in a single layer, working in batches if necessary to avoid overcrowding.
Air fry for about 10-12 minutes, flipping halfway through, until the chicken is golden brown and cooked through.
In a saucepan, combine sugar, water, vinegar, soy sauce, chili sauce, garlic, and ginger.
Bring to a simmer over medium heat.
Stir in the cornstarch slurry and continue to cook, stirring constantly, until the sauce thickens.
Toss the air-fried chicken in the sauce until evenly coated.