Cook the lo mein noodles according to package instructions until al dente. Drain and set aside.
In a small bowl, whisk together soy sauce, oyster sauce, hoisin sauce, sesame oil, sugar, white pepper, chicken broth, and cornstarch until smooth. Set the sauce mixture aside.
Heat vegetable oil in a large skillet or wok over medium-high heat.
Add the sliced chicken breast and cook for 4-5 minutes until no longer pink, stirring frequently.
Add the minced garlic and cook for 30 seconds until fragrant.
Add the shredded carrots, sliced bell pepper, and snap peas to the skillet. Stir-fry for 3-4 minutes until vegetables are crisp-tender.
Add the cooked noodles and green onions to the skillet.
Pour the sauce mixture over the noodles and vegetables. Toss everything together and cook for 2-3 minutes until the sauce thickens and coats the noodles evenly.
Remove from heat and serve immediately.