Bring a large pot of water to a boil and cook the lo mein noodles according to package directions. Drain and set aside.
Heat 1 tablespoon vegetable oil in a large skillet over medium-high heat. Add the sliced chicken, season with salt and pepper, and cook until no longer pink, about 5 minutes. Remove the chicken to a plate.
Add the remaining tablespoon of vegetable oil to the skillet. Stir in the garlic and ginger and cook for 30 seconds until fragrant.
Add the mixed vegetables and stir fry for 4 minutes until they begin to soften but still feel crisp.
Return the chicken to the skillet. Pour in the soy sauce and oyster sauce, then add the cooked noodles. Toss everything together for 2 minutes until the noodles are coated and heated through.
Drizzle with sesame oil and sprinkle with sliced green onions before serving.