In a large pot, melt butter over medium heat. Add the onion, carrots, and celery, and sauté for 5-7 minutes until vegetables begin to soften.
Stir in the minced garlic and cook for another minute until fragrant.
Pour in the chicken broth and add the thyme and bay leaf. Bring to a boil, then reduce heat and simmer for 15 minutes.
Add the egg noodles and cook according to package directions, typically 8-10 minutes.
Stir in the diced chicken and cook for another 3-4 minutes until heated through.
Remove the bay leaf, season with salt and pepper to taste, and stir in fresh parsley before serving.