1. Cut the chicken into long strips, about 5mm (1/4 inch) thick.
2. Heat oil in a wok or large frying pan. Add the garlic and chillies and cook, stirring for 1 minute, without browning. Add the chicken strips and stir-fry over a high heat for 4-5 minutes until cooked through. Stir in the soy sauce.
3. Stir in the basil leaves just before serving and heat through. Season with salt and pepper to taste.