Heat 2 tbsp oil to saute green chilli, red chilli and Chinese celery until fragrant. Drain and set aside.
Saute shallot, garlic, onion and ginger slices in the same saucepan. Add chicken pieces and pan-fry until golden yellow
Add seasoning mix. Cover, cook over medium heat for about 15-18 minutes until chicken is tender. Take out and let cool. Chop the chicken and arrange on plate.
Add thickening to the sauce left in pan. Cook until sauce thickens. Stir in chilli and Chinese celery. Pour sauce over chicken and serve.