Cook the egg noodles according to package instructions. Drain and set aside.
In a large skillet or wok, heat the vegetable oil over medium-high heat.
Add the sliced chicken to the skillet and season with salt and pepper. Cook for about 5-7 minutes, or until the chicken is browned and cooked through.
Add the broccoli, bell peppers, and carrots to the skillet. Stir-fry for an additional 3-4 minutes until the vegetables are tender-crisp.
Pour the teriyaki sauce over the chicken and vegetables, stirring to coat everything evenly. Cook for another 2 minutes.
Add the cooked noodles to the skillet, tossing everything together until well combined and heated through.
Remove from heat and garnish with chopped green onions and sesame seeds, if using.