Warm oil in a large pot over medium heat.
Sauté onion, carrots, and celery until softened and fragrant, about 5 minutes.
Stir in garlic; cook until aromatic, about 30 seconds.
Pour in broth; add thyme, parsley, salt, and pepper. Bring to a boil.
Submerge chicken; reduce heat to maintain a gentle simmer.
Cook until chicken is done, 12 to 15 minutes.
Transfer chicken to a board; shred with two forks.
Return shredded chicken to the pot; stir in egg noodles.
Simmer until noodles are tender, 6 to 8 minutes.
Stir in lemon juice and fresh parsley. Taste and adjust seasoning.