Melt 2 tablespoons butter in a large pot over medium heat. Add onions and celery and cook until tender, 4 to 5 minutes. Season with salt and pepper.
Add potatoes, cream of chicken, Cheddar cheese soup, and broth to the pot and season with Cajun seasoning, garlic powder, and onion powder. Simmer for 5 minutes. Add chicken and bacon to the soup.
Reduce heat to low, and simmer, stirring occasionally, 15 to 20 minutes more. Stir in sour cream and creamy mozzarella; remove from heat.
Serve garnished with shredded Cheddar, bacon, scallions, and crushed Ritz crackers.
