In a large pot, heat olive oil over medium heat. Add the diced onion, sliced carrots, and sliced celery heart. Cook until the vegetables are softened, about 5-7 minutes.

Add minced garlic, thyme, and oregano to the pot. Stir and cook for another 1-2 minutes until fragrant.

Pour in the can of petite diced tomatoes (with their juices) and sliced celery stalks. Stir to combine with the cooked vegetables.

Add chicken broth to the pot and bring the mixture to a simmer. Let it cook for about 10-15 minutes to allow the flavors to meld together.

Once the soup has simmered and the vegetables are tender, add the shredded cooked chicken to the pot. Stir to combine and let it simmer for an additional 5 minutes to heat through.

Stir in the fresh arugula, allowing it to wilt in the hot soup. Season the soup with salt and pepper to taste.

Ladle the Arugula Chicken Soup into bowls and garnish with chopped fresh parsley. Optionally, sprinkle grated Parmesan cheese over the top for added flavor.

Serve the soup hot and enjoy!