Prepare all ingredients by chopping the veggies and protein into bite-sized pieces.

Heat vegetable oil in a large skillet or wok over medium-high heat until shimmering.

Add the diced protein and sauté until fully cooked and golden brown.

Stir in the shredded cabbage, sliced carrots, and bell peppers; cook for about 5 minutes until slightly softened.

Add the yakisoba noodles to the pan, tossing gently to combine.

In a small bowl, mix together oyster sauce, soy sauce, and ketchup; pour over the noodle mixture and stir well.

Serve hot with extra sauce if desired.