Whisk soy sauce, oyster sauce, hoisin sauce, red wine vinegar, sesame oil, garlic powder, honey, chile sauce, and black pepper together in a bowl until marinade is smooth. Brush marinade onto steak strips and broccoli, reserving some for the noodles. Refrigerate for 4 hours to overnight.
Bring a large pot of lightly salted water to a boil. Cook chow mein noodles in the boiling water, stirring occasionally until tender yet firm to the bite, about 3 minutes. Drain.
Heat oil in a wok or deep skillet over medium heat; cook and stir onion for 3 minutes. Add garlic and beef-broccoli mixture; cook and stir until beef is cooked through, 1 to 2 minutes. Add noodles and reserved marinade; toss using tongs and cook until heated through, 1 to 2 minutes.
