Crumble the ground turkey or beef in a heavy Dutch oven or iron skillet. If desired, add oil to the skillet to keep the meat from sticking. Cook, stirring, over low heat until the meat is no longer pink, about 3 to 5 minutes. Add the Devil’s Backbone Seasoning and dried oregano. Toss to coat. Turn off the heat, and add the chili powder and ground cumin and toss to coat. Stir in the canned tomatoes and the jalapeño peppers. Fill one of the tomato cans with water and add to the skillet. Stir the mixture and bring to a boil over medium heat, then reduce to a simmer while you prepare the cornbread.
For the cornbread, place the cornbread mix, egg, oil, and buttermilk in a large bowl, and stir to just combine. Pour half of the batter in the bottom of a lightly greased 13-by 9-inch casserole dish (3-quart) and smooth the top with a spatula. Scatter half of the corn over the top. Turn off the heat under the meat, and spoon half of the meat mixture on top of the cornbread. Spread all of the sour cream over the top. Scatter half of the corn chips over the sour cream. Sprinkle half of the cheese on top of the corn chips. Repeat with the remaining cornbread batter, the remaining corn, the rest of the meat and the rest of the corn chips. Place the casserole in the oven.
Bake until the cornbread is cooked through and the casserole is bubbly, about 50 to 50 minutes. The baking time will differ depending on your casserole dish. When the cornbread tests done, remove the casserole from the oven, and scatter the top with the remaining cheese. Place the casserole back in the oven to let the cheese melt, about 3 minutes. Remove the casserole from the oven, and garnish with salsa, lettuce, tomato, and cilantro. Serve at once.