Preheat oven to 200°. Boil noodles according to package instructions. Drain. Heat 1 tbsp. each vegetable oil and sesame oil in a medium nonstick frying pan over medium-high heat. Spread noodles evenly in pan and cook, turning once, until browned and crisp, about 5 minutes per side. Keep warm in oven.
Meanwhile, cut chicken into thin strips. Season chicken with salt and pepper and set aside. Trim bases of bok choy and separate leaves; if longer than 3 in., cut in half crosswise. Rinse and thoroughly dry bok choy in a salad spinner. Combine oyster sauce, soy sauce, and 2 tsp. sesame oil in a small bowl; set aside.
Heat a wok or large sauté pan (not nonstick) over medium-high heat until hot when you wave your hand over the bottom. Add remaining 1 tbsp. each vegetable and sesame oil, the chiles, garlic, and ginger and cook, stirring, until fragrant, 10 seconds. Add chicken and sausage and stir-fry until chicken is no longer pink, 1 to 1 1/2 minutes. Add bok choy and cook, tossing with tongs, until beginning to wilt, 1 minute. Add oyster-soy mixture and cook until sauce boils, 30 to 45 seconds. Slide pancake onto a cutting board and top with stir-fry. Serve immediately.
*Find fresh Chinese noodles in the refrigerated section of your grocery store, usually near the produce, and oyster sauce in the Asian-foods aisle. Find lop chong at Asian markets and at amazon.com.