Boil the Potatoes: In a medium pot, cover potatoes with water and bring to a boil. Cook 12–15 minutes until tender. Drain and mash with butter, milk, and salt.
Cook the Noodles: Boil egg noodles in salted water according to package instructions. Drain and set aside.
Make the Gravy: In a saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute. Slowly whisk in chicken broth and milk. Add garlic powder, onion powder, salt, and pepper. Simmer until thickened.
Combine Chicken and Noodles: Stir shredded chicken and noodles into the gravy. Let simmer 3–5 minutes until everything is heated through and coated.
Serve: Spoon mashed potatoes onto each plate and top generously with the creamy chicken and noodles. Garnish with parsley if desired.