Cook the chicken: In a large skillet, heat olive oil over medium-high heat. Add chicken and cook until browned. Remove from skillet and set aside.
Sauté the onion: Add onion to the skillet and cook until softened, about 3-4 minutes.
Add the pineapple and sauce: Stir in pineapple chunks, soy sauce, honey, rice vinegar, garlic, and red pepper flakes (if using). Cook for 3-5 minutes, allowing the sauce to thicken.
Combine: Return chicken to the skillet, toss to coat the chicken in the sauce, and cook for an additional 2-3 minutes to heat through.
Serve: Serve the pineapple chicken mixture over cooked rice.
Notes
Optional Red Pepper Flakes: Add for a bit of heat to balance the sweetness of the pineapple.
Serve with steamed vegetables or a side of greens for a complete meal.
For added flavor, top with chopped cilantro or a squeeze of lime juice.