1. 1. Preheat the oven to 375°F (190°C).

2. 2. In a large skillet, cook boneless chicken until no longer pink. Shred the chicken and set aside.

3. 3. In the same skillet, sauté diced tomatoes, corn, and minced garlic until softened.

4. 4. Add canned chicken broth, grated parmesan cheese, cheddar cheese, cream cheese, and fat-free sour cream to the skillet. Stir until well combined and creamy.

5. 5. Stir in ranch dressing and shredded chicken. Cook for another few minutes.

6. 6. Pour the mixture into a baking dish.

7. 7. Top with slices of white bread and mashed potatoes.

8. 8. Bake in the preheated oven for 25-30 minutes or until bubbly and golden brown.

9. 9. Serve hot and enjoy!