Cook the lo mein noodles according to package instructions. Drain and set aside.
In a wok or large skillet, heat the vegetable oil over high heat.
Add the minced garlic and cook for 1 minute until fragrant.
Add the shrimp and stir-fry for 2-3 minutes until pink and cooked through. Remove shrimp from the pan and set aside.
In the same pan, add the sliced carrots, bell peppers, mushrooms, and snow peas. Stir-fry for 3-4 minutes until vegetables are crisp-tender.
In a small bowl, mix together soy sauce, oyster sauce, hoisin sauce, sesame oil, and red pepper flakes.
Return the shrimp to the pan with the vegetables. Add the cooked noodles and sauce mixture. Stir-fry for an additional 2-3 minutes until everything is well coated and heated through.
Garnish with sliced green onions and serve hot.