Cook the lo mein noodles according to package instructions. Drain and set aside.

In a large skillet or wok, heat 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 broccoli, bell pepper, and snap peas. Stir-fry for about 3-5 minutes until the vegetables are tender-crisp.

Add the garlic and ginger to the skillet and stir-fry for an additional minute until fragrant.

Return the cooked beef to the skillet. Add the cooked lo mein noodles, soy sauce, oyster sauce, sesame oil, and sugar. Toss everything together until well combined and heated through, about 2-3 minutes.

Season with salt and pepper to taste. Garnish with chopped green onions before serving.