Place the chopped chicken thighs in a bowl. Add salt, pepper, garlic powder, and 1 tbsp cornflour. Toss until coated.
Add the oil and toss again to coat. Preheat your air fryer to 400°F (200°C) for 3 minutes.
Add chicken to the air fryer basket in a single layer. Cook for 10 minutes, shake the basket, then cook for another 8–10 minutes until golden and cooked through.
While the chicken cooks, combine soy sauce, honey, ketchup, brown sugar, and water in a pan. Heat over medium.
Once simmering, add the cornflour slurry. Stir until the sauce thickens, then remove from heat.
Toss the cooked chicken in the sauce. Sprinkle with sesame seeds and sliced spring onions before serving.