In a large skillet, fry chicken breasts in vegetable oil until the chicken just begins to brown.
Stir onions, green bell pepper and red bell pepper into the skillet 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 skillet from the heat. Season with salt, pepper and red pepper flakes.
Transfer the mixture to a 9- x 13-inch baking dish and bake in a 425ºF (220ºC) oven for 45 minutes, or until the vegetables cook down and the chicken is tender.