Heat vegetable oil in a large pan over medium-high heat.
Add minced garlic and chopped chilies; sauté for about 30 seconds.
Add sliced chicken and stir-fry until cooked through (about 5-7 minutes).
Mix soy sauce, oyster sauce, fish sauce, and sugar in a bowl.
Pour the sauce mixture over the chicken and stir to coat evenly.
Add the fresh Thai basil leaves and stir-fry for another minute.
Remove from heat and let stand for a minute.
Serve hot over jasmine rice.
Garnish with additional basil leaves if desired.
Enjoy your delicious homemade Thai basil chicken!