Cook the lo mein 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 and season with salt and pepper. Cook until browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the minced garlic and sauté for about 30 seconds until fragrant.
Add the bell peppers, snap peas, and carrots to the skillet. Stir-fry for about 3-4 minutes until the vegetables are tender-crisp.
Return the cooked chicken to the skillet. Add the cooked lo mein noodles, soy sauce, oyster sauce, sesame oil, and ground ginger. Toss everything together and cook for an additional 2-3 minutes until heated through.
Remove from heat and stir in the chopped green onions. Serve hot, garnished with sesame seeds if desired.