In a large mixing bowl, combine ground chicken, breadcrumbs, parmesan cheese, beaten egg, minced garlic, diced onion, and a pinch of salt and pepper. Gently mix until combined and shape into 1-inch meatballs.

Heat olive oil in a large pot over medium heat. Add meatballs in batches, searing for 4-5 minutes until golden brown. Remove and set aside.

In the same pot, add additional olive oil if needed, then sauté chopped onion, diced carrots, and chopped celery over medium heat for 5-7 minutes until softened.

Pour in chicken broth and water, scraping the bottom of the pot to release any bits. Bring to a gentle simmer.

Stir in small pasta and let simmer for 8-10 minutes until al dente, stirring occasionally.

Return the meatballs to the pot along with fresh spinach, stirring gently and simmering for another 2-3 minutes.

Taste and adjust seasoning. Ladle the soup into bowls and serve hot, with crusty bread.