Heat 1 tablespoon oil in a large nonstick skillet over medium-high heat. Add chicken; cook, stirring occasionally, until golden brown and cooked through, about 5 minutes. Transfer to a plate.
Heat the remaining 1 tablespoon oil in the skillet over medium-high heat. Add peppers and onions; cook, stirring often, until tender-crisp, about 3 minutes. Return the chicken to the pan and stir in pineapple and teriyaki sauce. Cook, stirring often, until the sauce thickens and coats the chicken, 2 minutes.
Divide rice among 4 plates. Top with the chicken and vegetable mixture.
