Marinate the Chicken
In a bowl, mix sliced chicken with soy sauce, cornstarch, and sesame oil. Toss to coat and set aside while preparing other ingredients.

Cook the Noodles
Bring a large pot of water to a boil. Cook noodles according to package instructions until al dente. Drain, toss with a bit of sesame oil to prevent sticking, and set aside.

Make the Sauce
In a small bowl, whisk together soy sauce, oyster sauce, hoisin sauce, brown sugar, chicken broth, and toasted sesame oil. Set aside.

Stir-Fry the Chicken
Heat vegetable oil in a large skillet or wok over medium-high heat. Add marinated chicken and stir-fry for 4-5 minutes until cooked through. Remove from pan and set aside.

Stir-Fry the Veggies
In the same pan, add a little more oil if needed. Sauté minced garlic (and ginger, if using) for about 30 seconds until fragrant. Add bell peppers, carrots, and snap peas; stir-fry for 3-4 minutes until crisp-tender.

Combine Everything
Return the chicken to the pan. Pour in sauce and toss to coat. Simmer 1-2 minutes until the sauce thickens. Add noodles and green onions, toss gently, and heat through for 1 more minute. Garnish with reserved green onions and serve!