Heat a wok or large, deep skillet over medium-high heat. Add the oil and swirl it to coat the surface. Add the garlic and onion; stir briefly until they begin to release their aroma, about 45 to 60 seconds. Add the chicken pieces, tossing well so the meat browns evenly.
Add the fish sauce, soy sauce, water, and sugar; cook 2 to 3 minutes, tossing now and then, just until the chicken is cooked and the seasonings form a thin smooth sauce. Add the chile peppers and basil; toss and stir fry just until the basil just begins to wilt.
Transfer to a serving plate and serve hot or warm with cooked rice, if you desire. Garnish with some leftover basil leaves.
Makes 4 servings.
* The U.S. Department of Agriculture, as well as food agencies in the United Kingdom and elsewhere, advises against washing poultry. Rinsing chicken will not remove or kill much bacteria, and the splashing of water around the sink can spread the bacteria found in raw chicken. Cooking poultry to 165 degrees Fahrenheit effectively destroys the most common culprits behind food-borne illness.
Thai Chicken Basil Recipe: https://whatscookingamerica.net/poultry/thaichickenbasil.htm