Cook the Noodles: Bring a large pot of water to a boil. Add the chow mein noodles and cook according to package instructions until al dente. Drain and set aside.

Prepare the Vegetables: While the noodles are cooking, chop all the vegetables. Ensure the carrots are thinly sliced, the cabbage is shredded, and the bell peppers are sliced into thin strips.

Heat the Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.

Stir-Fry the Vegetables: Add the minced garlic and stir-fry for about 30 seconds until fragrant. Then, add the sliced carrots, cabbage, and bell peppers. Stir-fry for about 3-4 minutes until the vegetables are tender but still crisp.

Add the Noodles: Toss in the cooked chow mein noodles and stir to combine with the vegetables.

Season the Dish: Add the soy sauce, oyster sauce (if using), and sesame oil. Stir well to evenly coat the noodles and veggies. Season with salt and pepper to taste.

Incorporate Protein (Optional): If using cooked protein, add it to the skillet and mix well until heated through.

Finish with Green Onions: Add the chopped green onions and bean sprouts. Stir-fry for an additional 1-2 minutes.

Serve: Transfer the chow mein to serving plates. Enjoy hot!