First things first, fire up your oven and preheat it to 375°F (190°C).
Build Your Flavorful Base: Grab a large, oven-safe skillet and set it over medium heat. Add your finely diced onion and sauté for about 2-3 minutes until it starts to soften, add your minced garlic and saute for only 30-60 seconds. Now, add the ground beef to the skillet. Break it apart as it cooks, browning it thoroughly for 6-8 minutes.
Next, stir in the diced tomatoes (along with their juices) and the tomato paste. Let this cook on medium/low for 3-5 minutes, allowing the tomatoes to soften and their flavors to deepen.
Add your spice blend. Cook for just 1-2 more minutes, stirring constantly, to let those spices truly bloom and become fragrant.
Finally, mix in the drained and rinsed black beans, corn, and the enchilada sauce. Give everything a good stir and let it simmer for 2-3 minutes, just to let the flavors meld.
Assemble and Bake: If your skillet isn't oven-safe, transfer the entire mixture to a baking dish. Otherwise, keep it in the same skillet! Now, artfully arrange the tortilla chips on top of the beef mixture, creating a delicious, crunchy layer. Evenly sprinkle the shredded cheddar and Monterey Jack cheese blend over the chips.
Pop the skillet into your preheated oven and bake for 8-10 minutes, or until that cheese is beautifully melted and bubbly.
Garnish and Serve: Once it's out of the oven, get ready to dive in! Garnish your skillet with fresh cilantro, diced avocado, and a dollop of cool sour cream. Serve it warm and enjoy every cheesy, flavorful bite!