Combine cornstarch, garlic powder, onion powder, salt, and pepper in a large bowl.
Dice chicken into ½-inch pieces and toss with the cornstarch mixture to coat evenly.
Heat olive oil in a skillet over medium-high heat. Cook chicken in a single layer for 3-4 minutes until golden, then stir and cook for another 5-6 minutes until cooked through.
Reduce heat to medium-low. Add butter, garlic, and red pepper flakes; stir until butter melts and garlic is fragrant.
Remove from heat, stir in parsley, and serve immediately.
Notes
Serve with rice or vegetables for a complete meal.