Preheat your oven to 400°F and grease a 9x13-inch baking dish.
In a large bowl, stir together the cornmeal, flour, sugar, baking powder, and salt.
In a separate bowl, whisk together the milk, vegetable oil, and eggs until well combined. Pour the wet ingredients into dry ingredients. Stir until just combined. Transfer to the greased baking dish and spread out evenly with a spatula. Bake for 30 to 35 minutes. Set aside to cool, then crumble the bread.
In a large soup pot or Dutch oven, add the chicken thighs, celery, carrot, onion, pepper, garlic, chicken bouillon, chicken bouillon base (optional), dried herb mix, garlic powder, thyme, sage, salt, and pepper. Pour in the water and stir to combine. Bring to a boil, reduce heat to low and simmer for 1 hour. Strain the broth through a large mesh sieve into a bowl. Debone the chicken and set aside.
Preheat the oven to 350°F and grease a 9x13-inch baking dish.
In a large skillet, cook the bacon. Add the onions, peppers, and celery. Cook until soft.
In a large bowl, add the bacon and veggie mixture, crumbled cornbread, deboned chicken, 1 1/3 cups warm chicken broth, cream of chicken, cream of celery, fresh sage, and spices. Stir until well combined. Transfer to the prepared baking dish. Bake uncovered at 350°F for 30 minutes. Increase the heat 375°F and bake for 10 additional minutes, until golden brown.