In a mixing bowl, coat chicken cubes with beaten egg, cornflour, plain flour, salt, and pepper until evenly coated.
Heat oil in a deep pan and fry chicken in batches until golden and crisp. Remove and drain on paper towels.
In a separate wok or large pan, heat vegetable oil. Add garlic, ginger, and onion. Stir-fry until fragrant.
Add bell pepper and green chili, stir-fry for 2-3 minutes until slightly softened.
Mix in ketchup, soy sauce, sweet chili sauce, rice vinegar, and honey. Stir until the sauce thickens slightly.
Toss the fried chicken into the sauce, coating evenly.
Garnish with chopped spring onions and sesame seeds before serving.