In a large pot, heat the olive oil over medium heat. Add the diced onion and sauté for 3-4 minutes until softened.
Stir in the minced garlic and continue to cook for an additional 1 minute until fragrant.
Add the diced carrots and celery to the pot, and sauté for another 5 minutes until they start to soften.
Add the chicken broth, thyme, oregano, and season with salt and pepper. Bring the mixture to a boil.
Once boiling, carefully add the chicken breasts to the pot. Reduce the heat to medium-low and let simmer for about 15-20 minutes, or until the chicken is cooked through.
Remove the chicken breasts from the pot and set aside to cool slightly. Shred the chicken with two forks and return it to the pot.
Add the cooked rice or quinoa along with the lemon juice and zest. Stir well to combine. Simmer for an additional 5 minutes to heat everything through.
Taste and adjust seasoning as needed.
Serve hot, garnished with fresh parsley.
Notes
Feel free to add more vegetables or adjust seasoning to your taste.