Sauté the Vegetables. Heat olive oil in a large pot or Dutch oven over medium heat. Add onion, garlic, carrots, and celery. Sauté for 3–5 minutes, until softened and fragrant.
Simmer the Broth. Pour in chicken broth, then add thyme, parsley, salt, black pepper, and bay leaf. Bring to a gentle simmer, allowing the flavors to meld for 10 minutes.
Add the Chicken & Noodles. Stir in shredded rotisserie chicken and let it warm through. If using noodles, add them now and cook according to package directions.
Finish & Serve. Remove the bay leaf and stir in lemon juice (if using). Taste and adjust seasoning as needed. Serve hot, garnished with fresh parsley or a sprinkle of black pepper.