Heat olive oil in a large pot over medium heat.
Add chopped onions, carrots, and celery; sauté for 5 minutes.
Stir in minced garlic; cook for another minute.
Pour in chicken broth and bring to a boil.
Reduce heat and add shredded chicken.
Add cooked rice to the pot.
Season with salt and pepper to taste.
Simmer for 15 minutes to allow flavors to meld.
Remove from heat and let cool slightly.
Garnish with fresh parsley before serving.