Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, carrots and celery and cook for 5–6 minutes, stirring now and then, until the onion is soft.
Stir in the garlic and cook for 30 seconds.
Add the broth, chicken, thyme, bay leaf, salt and pepper. Bring to a boil, then reduce the heat, cover and simmer for 15–18 minutes, until the chicken reaches 165°F in the thickest part.
Move the chicken to a cutting board and shred it with two forks.
Bring the soup back to a boil. Add the noodles and cook for 6–8 minutes, until tender.
Return the chicken to the pot and remove the bay leaf. Taste and add more salt and pepper if needed.
Sprinkle with parsley and serve hot.