In a large bowl, combine the sweet chili sauce, soy sauce, rice vinegar, honey, garlic powder, onion powder, black pepper, salt, and red pepper flakes. Mix well to create the marinade.
Add the chicken thighs to the marinade, ensuring they are well coated. Cover the bowl and refrigerate for at least 30 minutes, or up to 4 hours for more flavor.
Preheat the air fryer to 380°F.
Remove the chicken thighs from the marinade, allowing excess marinade to drip off. Discard the remaining marinade.
Place the chicken thighs in the air fryer basket, skin side up, ensuring they are not overcrowded.
Cook the chicken thighs in the air fryer for 25-30 minutes, flipping halfway through, until the internal temperature reaches 165°F and the skin is crispy.
Once cooked, remove the chicken from the air fryer and let it rest for 5 minutes. Garnish with chopped green onions and sesame seeds before serving.