Cook the egg noodles according to package instructions. Drain and set aside.
In a large skillet or wok, heat the vegetable oil over medium-high heat. Add the sliced beef and cook until browned, about 3-4 minutes. Remove the beef from the skillet and set aside.
In the same skillet, add the minced garlic and sauté for about 30 seconds until fragrant.
Add the broccoli, bell pepper, and carrots to the skillet. Stir-fry for 4-5 minutes until the vegetables are tender-crisp.
Return the cooked beef to the skillet. Add the cooked noodles, soy sauce, oyster sauce, sesame oil, salt, and pepper. Toss everything together and cook for an additional 2-3 minutes until heated through.
Stir in the chopped green onions and serve immediately.