Sweat diced onion in olive oil with sea salt over medium heat. Add garlic and stir. Add tomatoes, chicken broth, Italian seasoning, basil, ground black pepper and meatballs over medium high heat. When soup comes to a boil, decrease heat and allow to simmer for 10 minutes. Stir in fresh spinach and tortellini. Allow to simmer another 5 minutes. Remove from heat. Season additionally to taste, if desired. Serve.