Gather all ingredients and chop vegetables into bite-sized pieces.
Cook lo mein noodles according to package instructions until al dente; drain and set aside.
Heat a large skillet or wok over medium-high heat. Add sesame oil and sauté the chicken until golden brown and fully cooked, about 6-8 minutes.
Remove cooked chicken from skillet.
In the same pan, stir-fry bell peppers, carrots, and green onions until tender yet crisp, about 3-4 minutes.
Return cooked chicken to the skillet with vegetables.
Add lo mein noodles, soy sauce, sesame oil, minced garlic, and any additional spices.
Toss everything together until well mixed.
Serve hot with extra soy sauce if desired.