Warm up a wok or large frying pan over medium-high heat. Add 1-2 Tbsp. oil plus garlic and minced chili, if using. Stir-fry until fragrant (30 seconds). Add marinated chicken. When wok/pan becomes dry, or marinade starts to stick on the pan, add a little chicken stock, 1-2 Tbsp. at a time, to keep the chicken frying nicely (5-7 minutes, until cooked is cooked).