Cook lo mein noodles according to package directions. Drain and set aside.
In a large skillet or wok, heat vegetable oil over medium-high heat.
Add sliced steak, season lightly with salt and pepper, and cook until browned. Remove and set aside.
In the same pan, add garlic, ginger, and broccoli. Sauté for 3–4 minutes until broccoli is tender-crisp.
In a bowl, mix soy sauce, oyster sauce, hoisin sauce, brown sugar, and sesame oil.
Return steak to the pan, pour in the sauce mixture, and toss everything to combine.
Add noodles and stir-fry everything for 2–3 minutes until heated through and coated.
Garnish with sliced green onions and sesame seeds if desired. Serve hot.