Cook the Noodles: Boil the chow mein noodles according to package instructions, typically for 3-4 minutes, until al dente. Drain the noodles and cool them down by rinsing under cold running water, which halts the cooking process and prevents them from becoming mushy. Set aside.

Prepare the Sauce: In a small bowl, whisk together the soy sauce, oyster sauce, hoisin sauce, sesame oil, and sugar. Add the broth if desired for extra moisture and flavor. Set aside.

Stir-Fry the Protein (if using): In a large wok or skillet, warm 1 tablespoon of vegetable oil over medium-high heat until it shimmers, creating the ideal base for your cooking. Add the chicken (or other protein) and stir-fry for 2-3 minutes, until cooked through. Remove from the wok and set aside.

Stir-Fry the Vegetables: Incorporate the last tablespoon of vegetable oil into the wok, allowing it to blend with the heated surface for enhanced cooking. Add the sliced onion, bell pepper, and carrot, and stir-fry for 2 minutes until slightly softened. Add the shredded cabbage, green onions, and bean sprouts, and continue to stir-fry for another 2-3 minutes.

Combine Noodles, Protein, and Sauce: Add the cooked noodles and any cooked protein back into the wok. Drizzle the sauce over the noodles and toss to ensure each strand is evenly coated. Stir-fry for 2-3 minutes until the noodles are evenly coated in the sauce and heated through.

Serve Hot: Transfer the chow mein to a serving dish and garnish with extra green onions if desired. Serve hot and enjoy!