In a large frying pan, fry chicken breast in vegetable oil until the chicken just begins to brown.
Stir onions, green peppers and red peppers into the frying pan with the chicken. Saute until the onions are translucent. When the vegetables are translucent, stir in the garlic and coconut milk. Let the mixture cook 5 to 8 minutes before removing the frying pan from the heat. Season with salt, pepper and red chilli flakes.
Transfer the mixture to a baking dish and bake in a 220 C / Gas 7 oven for 45 minutes, or until the vegetables cook down and the chicken is tender.