In a bowl, mix soy sauce, teriyaki sauce, BBQ sauce, mirin, brown sugar, ginger, garlic, and black pepper. Add the sliced pork and let it marinate for 10 minutes.
Prepare the noodles
If using pre-cooked yakisoba, rinse them under warm water to loosen. If using fresh, cook them according to package instructions and drain.
Sear the pork
Heat 1 tbsp of vegetable oil in a large skillet or wok over medium-high heat. Add the marinated pork and stir-fry until browned and slightly caramelized, about 5 minutes. Remove from the pan and set aside.
Stir-fry the veggies
In the same pan, add onions, carrots, bell peppers, and cabbage. Stir-fry for 3 minutes until slightly softened.
Toss in the noodles
Add the yakisoba noodles to the pan. Drizzle in oyster sauce and sesame oil, then toss to combine.
Finish with sauce & pork
Return the pork to the pan and pour in any leftover marinade. Stir-fry for another 2-3 minutes until everything is well coated and heated through.
Serve & garnish
Transfer to plates, then sprinkle with sesame seeds, green onions, and nori strips for extra flavor.