Preheat air fryer to 400F (200C).
In a large mixing bowl, combine the cubed chicken with 40g cornstarch, sea salt, black pepper, and garlic powder. Toss until each piece is thoroughly and evenly coated.
Spray the air fryer basket with avocado oil. Arrange the chicken in a single layer, ensuring pieces do not overlap.
Air fry for 12-15 minutes, shaking the basket halfway through, until the exterior is golden-brown and internal temperature reaches 165F (74C).
While the chicken is air-frying, combine orange juice, zest, tamari, sweetener, rice vinegar, ginger, garlic, and red pepper flakes in a medium saucepan.
Bring the mixture to a simmer over medium heat for 5-7 minutes to reduce the volume slightly.
Whisk the cornstarch slurry into the sauce and continue to cook for 1-2 minutes until the glaze thickens to a glossy consistency.
Transfer the crispy chicken to a clean bowl, pour the orange glaze over the top, and toss until fully encapsulated.
Serve immediately over steamed broccoli or jasmine rice for a complete high-protein meal.