Cook the lo mein noodles in salted boiling water until al dente according to package instructions. Drain and set aside.

In a large skillet or wok over medium-high heat, add 1 tbsp sesame oil. Sauté the chicken pieces until golden brown and cooked through for about 5–7 minutes.

Add minced garlic, bell peppers, and carrots; stir-fry for another few minutes until vegetables are tender yet crisp.

In a small bowl, whisk together remaining sesame oil, soy sauce, and brown sugar. Pour over the chicken and vegetables.

Add the drained lo mein noodles to the skillet and mix everything well until coated in sauce.

Serve hot garnished with green onions.