Season the cubed chicken breast with salt, pepper, and onion powder.
In a large, deep skillet over medium-high heat, add 1 tablespoon of olive oil and the cubed chicken breast. Saute until cooked through, approximately 10 minutes, and set aside.
Add remaining tablespoon of olive oil to the pan along with the garlic, red and green bell peppers, and pineapple. Saute until peppers have softened, approximately 5 minutes. Set aside.
Add the cornstarch to the pineapple juice and stir until fully combined.
Add ketchup, soy sauce, brown sugar, rice vinegar, ground ginger, and garlic to the skillet. Stir together over medium-high heat. Add the pineapple juice and cornstarch mixture stirring together so there are no lumps.
Cook sauce until it thickens enough to coat your spoon, approximately 5-10 minutes.
Add chicken, peppers, and pineapple to the sauce and stir to coat.
Serve over white rice as a meal or on skewers as an appetizer.