Heat olive oil in a large skillet over medium-high heat.
Season the chicken with salt and pepper and cook until browned and cooked through, about 6-7 minutes. Remove from skillet and set aside.
In the same skillet, add the bell peppers, broccoli, and snap peas. Stir-fry for 4-5 minutes until tender-crisp.
Return the chicken to the skillet and pour in the teriyaki sauce. Stir to coat evenly and cook for an additional 2-3 minutes.
Garnish with sesame seeds, if desired, and serve hot over cooked rice.