Preheat the oven to 375°F (190°C) and spray a 9x13-inch casserole dish with avocado cooking spray.

In a large skillet, heat olive oil over medium heat. Add onions and green peppers and cook, stirring, until softened, about 2 to 3 minutes. Add garlic and sauté for 30 seconds.

Add ground beef to the skillet and cook until no longer pink, breaking up large pieces. Continue stirring and cook until brown, about 5 minutes. Drain excess fat and reduce the heat to medium-low.

Stir in tomatoes and green chilies with juice, tomato paste, diced potatoes, cumin, oregano, chili powder, and salt and pepper to taste. Simmer until fragrant and saucy, about 10 to 12 minutes. Remove from the heat and stir in olives and raisins. Pour into prepared casserole dish.

Combine Cheddar and Monterey Jack cheeses and sprinkle half of the cheese mixture on top of the picadillo mixture. Reserve the remaining cheese for later use.

In a large mixing bowl, stir together the corn muffin mix, chili powder, egg, milk, and sour cream. When well blended, stir in chopped jalapeños. Spread cornbread mixture in an even layer over the casserole.

Bake in the center of the preheated oven until the cornbread is browned and firm to the touch, about 35 to 40 minutes. A toothpick inserted into the center of the cornbread should come out clean.

Remove from the oven and cool on a wire rack for about 15 minutes. Sprinkle the remaining cheese on top of the warm casserole.