Preheat your oven to 375°F (190°C), and lightly grease a 9x13-inch baking dish.

In a large skillet over medium heat, brown the ground beef until fully cooked. Drain any excess fat.

Add the chopped onion, red bell pepper, green bell pepper, and minced garlic to the skillet. Sauté until the vegetables are soft, about 5 minutes.

Stir in the taco seasoning, oregano, salt, and pepper. Mix well to combine the flavors.

Add the tomato paste, the can of diced tomatoes with green chilies, and the can of black beans Stir to combine, allowing the mixture to simmer for about 3 minutes.

In the prepared baking dish, place a single layer of tortillas at the bottom of the baking dish. Spread half of the refried beans over the tortillas. Then, spread half of the beef and bean mixture over the refried beans, followed by half of shredded Colby Jack cheese. Repeat the layering process with the other half of the ingredients, finishing with a layer of cheese on top.

Cover the dish with aluminum foil and bake in the preheated oven for 20 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden brown.

Allow the casserole to cool for a few minutes before slicing. Serve hot with your favorite toppings such as sour cream, sliced jalapenos, or chopped cilantro. Enjoy!