Heat vegetable oil in a large pan over medium heat.
Add minced garlic and sliced chilies; sauté until fragrant.
Increase heat to high and add chicken pieces.
Stir-fry chicken until browned and cooked through, about 5-7 minutes.
Mix in fish sauce, soy sauce, oyster sauce, and sugar.
Toss chicken until evenly coated with the sauces.
Add fresh basil leaves and stir until wilted.
Taste and adjust seasoning if necessary.
Serve over jasmine rice.
Garnish with additional basil leaves if desired.