In a bowl, combine shrimp with soy sauce, salt, pepper, and garlic powder. Set aside while you prep everything else.
Cook the noodles according to package directions. Drain and set aside.
In a large skillet or wok, heat 1 tbsp oil over medium-high heat. Add shrimp and cook for 2–3 minutes per side, or until pink and just cooked through. Remove and set aside.
Add remaining oil to the pan. Stir-fry garlic, ginger, green onion, yellow onion, carrots, broccoli, cabbage, and bell peppers for 4 minutes until tender-crisp.
In a small bowl, whisk together soy sauce, hoisin, oyster sauce, sesame oil, rice vinegar, brown sugar, and cornstarch until smooth.
Add cooked noodles and shrimp back to the pan. Pour in the sauce and toss everything together for 2–3 minutes until well coated and heated through.
Garnish with extra green onions or sesame seeds if desired. Serve hot and enjoy!