1. Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking dish and set aside.
2. In a large skillet, heat olive oil over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes.
3. Add the minced garlic and cook for another minute until fragrant.
4. Increase the heat to medium-high and add the ground beef. Cook until browned, breaking it apart with a wooden spoon, about 5-7 minutes. Drain excess fat if necessary.
5. Stir in the taco seasoning, black beans, and diced tomatoes with green chilies. Let it simmer for 5 minutes to allow the flavors to meld.
6. Layer half of the slightly crushed Doritos in the bottom of the prepared baking dish.
7. Spoon the beef mixture over the Doritos, spreading it evenly.
8. Dollop the sour cream over the beef mixture and spread gently with a spatula.
9. Sprinkle the shredded cheddar cheese over the sour cream layer.
10. Top with the remaining crushed Doritos.
11. Bake in the preheated oven for 20-25 minutes until the cheese is melted and bubbly.
12. Remove from oven and let it cool for a few minutes before serving.

As you prepare this dish, remember the importance of balance in flavor. It’s a lesson I learned from my first cooking mishap with an over-salted chili. Taste as you go—you can always adjust the seasoning to your preference.