Heat olive oil in a soup pot on medium heat. Add onion, carrots, and celery to the pan. Cook for 5 minutes or until the veggies start to soften.
Add broth, pepper, garlic powder, and rosemary. Let simmer for 10 minutes.
Add the orzo and cannellini beans. Cook for 8 minutes or until the orzo is done to your liking.
Finally, add the lemon juice, chicken, and spinach. Let cook for a few minutes until the spinach is wilted.
Serve with fresh rosemary, Italian parsley, or basil.