Combine chicken, 1 of the onions, quartered, 1 coarsely cut carrot, parsley, and bay leaves in a large soup pot or Dutch oven and cover with water. Add lid.
Bring to a simmer, and allow to cook gently until the chicken is cooked through, about 15 minutes.
When chicken is done, remove to platter to cool. Fish veggies out of the broth and transfer broth to a bowl or large measuring cup.
Add uncooked sausage to pot and add about 1/2 inch of water. Bring to a boil and allow to cook for a few minutes until the sausage firms up. If using a cooked sausage (like andouille), skip the par-cooking and proceed to the next step.
Remove sausage from pot and slice it on the diagonal. Add back to pot and cook on medium high heat until browned. Finely chop remaining onion and carrot; add to sausage once the sausage is browned.
Add stock and water totaling 4 cups into pot. Add can of tomato sauce and one half of an additional can of water. Add chicken soup base and 1 tablespoon of cajun seasoning and allow broth to cook over medium heat until lightly bubbling.
Meanwhile, make the meatballs: thoroughly combine bread crumbs, 1/2 teaspoon of Cajun seasoning and egg. Add meat and mix until uniform. Shape into tiny meatballs, about 1 teaspoon each.
Drop meatballs into lightly boiling broth and allow to cook through - at least 10 minutes, but for up to an hour.
Shred cooled chicken. Add chicken, pasta and spinach to soup 15 minutes before serving, and stir occasionally to prevent sticking.
Serve with additional Cajun Seasoning and plenty of Tabasco Sauce.