Bring a large pot of salted water to a boil. Add the noodles and cook according to package instructions until al dente. Drain and set aside.
In a large skillet or wok, heat the vegetable oil over medium heat. Add the diced onion and cook until translucent, about 3 minutes.
Stir in the minced garlic and ground beef. Cook until the beef is browned and cooked through, breaking it apart with a spoon, about 5-7 minutes.
Add broccoli florets and sliced carrots to the skillet. Stir and cook for an additional 3-4 minutes until the vegetables are tender.
In a small bowl, mix together the soy sauce, oyster sauce, hoisin sauce, ginger, and a pinch of salt and pepper. Pour this sauce over the beef and vegetable mixture. Stir well to combine and allow to simmer for another 2-3 minutes.
Add the cooked noodles to the skillet and toss everything together until the noodles are well coated with the sauce. Cook for an additional minute to heat through.
Plate the mixture and garnish with chopped green onions if desired. Serve hot.