In a large skillet, heat the vegetable oil over medium-high heat. Add the chicken pieces and cook until browned and cooked through, about 5-7 minutes.

Add the broccoli, bell peppers, and snap peas to the skillet. Stir-fry for another 3-5 minutes until the vegetables are tender-crisp.

Pour the teriyaki sauce over the chicken and vegetables. Stir to coat everything evenly and cook for an additional 2-3 minutes until heated through.

Serve the teriyaki chicken and vegetables over a bed of cooked rice.

Garnish with sliced green onions and sesame seeds, if using.