Prepare the noodles following the directions on the package. Once cooked, drain them thoroughly in a colander, then rinse under cold running water to stop the cooking process and prevent sticking. Set the noodles aside while you prepare the rest of the dish.
Pour 1 tablespoon of the oil into a wok or large nonstick frying pan and heat it over high heat until shimmering. Add the chicken pieces and stir-fry vigorously for about 2 minutes, tossing frequently, until they turn golden brown on all sides and are cooked through completely. Using a slotted spoon, lift the chicken out of the pan and transfer it to a plate, setting it aside temporarily.
Add the remaining oil to the same pan and let it heat up again. Toss in the chile, ginger, and lemongrass, followed immediately by the shrimp, mushrooms, and peas. Stir-fry this colorful mixture for 1 minute, keeping everything moving to prevent burning. Next, pour in the soy sauce, lime juice, and fish sauce, then season with salt and pepper to your liking. Return the reserved chicken to the pan along with the cooked noodles, tossing everything together energetically. Continue stir-frying for another 2–3 minutes until the shrimp turns bright pink and opaque, and everything is steaming hot throughout.
Transfer the fragrant stir-fry to serving bowls or plates and finish with a generous scattering of crushed peanuts and fresh cilantro leaves over the top. Serve immediately while piping hot.