Heat olive oil in a large pot over medium heat. Add onion, carrots, and celery. Sauté for 5-7 minutes until soft.
Add garlic, oregano, and thyme. Cook for 1 minute until fragrant.
Pour in the broth and add the raw chicken (and potatoes if using). Bring to a boil, then reduce to a low simmer.
Cover and simmer for 20 minutes or until chicken is cooked through.
Remove chicken, shred with two forks, and return to the pot.
Remove the bay leaf. Stir in fresh parsley, salt, and pepper. Serve warm with a squeeze of lemon.