Whisk together the barbecue sauce, soy sauce, garlic powder, and onion powder in a bowl until thoroughly combined.
In a medium pan turn the heat in high temperature with a cooking oil. Then fry the chicken until golden brown. Remove the chicken and set aside.
Pour the remaining sauce into a saucepan, place over medium heat, and bring to a boil. Whisk the cornstarch and water together in a small bowl until smooth. Whisk the cornstarch mixture into the sauce; reduce heat to a simmer, and allow the sauce to thicken, whisking constantly. Return the chicken to the dish, and pour the thickened sauce over the chicken to serve.