Begin by chopping the bell peppers and slicing the carrots and green onions. Cook the lo mein noodles in boiling salted water according to package directions until they are al dente, about 4–5 minutes. Drain and rinse under cold water.

In a large skillet, heat 2 tablespoons of vegetable oil over medium-high heat. Add chicken and cook for 6–8 minutes until golden brown and cooked through. Remove from skillet.

In the same skillet, stir-fry bell peppers, carrots, and half of the green onions for 3–4 minutes until tender-crisp.

Return the chicken to the skillet, add noodles, soy sauce, sesame oil, and garlic. Toss together for 2–3 minutes until heated through.

Remove from heat and garnish with remaining green onions. Serve immediately.