1. Heat a wok or large frying pan over high heat. Add oil and swirl to coat pan. Cook chicken with spices until browned, about 5 minutes. Add mango, lime juice, fish sauce, and half the onions and cook, stirring often, until mango starts to soften and release juices, about 3 minutes.
2. Serve over rice with remaining onions and basil sprinkled on top.