Place the chicken thighs, onion, carrots, celery, and garlic in a large pot. Add the water and bring to a boil over medium-high heat.
Reduce the heat to low, cover the pot, and simmer for 45 minutes until the chicken is fully cooked and the broth is flavorful.
Remove the chicken from the pot and set it aside to cool. Strain the broth if you prefer a clearer liquid, then return it to the pot.
Shred the chicken meat from the bones and discard the skin and bones. Add the shredded chicken back to the broth.
Stir in the herbes de Provence, diced tomatoes, and olives. Simmer uncovered for 15 minutes.
Season with salt and black pepper to taste. Ladle into bowls and top with fresh parsley before serving.