Place the chicken thighs in a large pot and cover with chicken broth. Bring to a gentle boil, skimming off any foam that rises to the surface.
Reduce the heat and let the chicken simmer uncovered for about 25 minutes until fully cooked and tender. The broth will become flavorful and aromatic.
Remove the chicken from the broth and let it cool slightly. Shred the chicken into bite-sized pieces using two forks.
Add sliced carrots, celery, and minced garlic to the broth. Increase the heat and bring the mixture back to a simmer. Cook for about 10 minutes until the vegetables are tender.
Stir in the egg noodles and cook until they are just tender, about 8 minutes. Keep the broth at a gentle simmer to avoid breaking the noodles.
Mix in the shredded chicken, along with lemon zest and chopped fresh herbs. Stir well to combine all flavors evenly.
Season the soup with salt and pepper to taste. Let it simmer for an additional 2-3 minutes to meld the flavors and warm through.
Taste and adjust seasoning if needed. The broth should be bright, savory, and fragrant with subtle lemon and herb notes.
Serve the hot soup in bowls, garnished with a sprinkle of additional herbs or lemon zest if desired.
