Cook the Noodles: Cook the egg noodles according to the package directions in salted water. Drain them and set aside.
Sauté Vegetables: Melt the butter in a large skillet over medium heat. Add the diced onion, minced garlic, and thawed mixed vegetables to the skillet.
Season: Season the vegetables with dried thyme, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Stir to combine. Cook until the onions are soft, about 5 minutes.
Thicken Sauce: Stir in the all-purpose flour until the vegetables are fully coated.
Create Sauce: Add the chicken broth and heavy cream to the skillet and bring the mixture to a simmer.
Simmer: Stir the sauce occasionally until it has thickened to your desired consistency, about 5 minutes.
Combine: Add the cooked pasta and shredded chicken to the sauce mixture. Stir everything together gently to combine.
Finish Seasoning: Season the pasta mixture with additional salt and pepper to taste.
Serve: Garnish with fresh parsley, if desired, and serve hot.