Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper or aluminum foil for easy cleanup. This high temperature ensures the chips stay crispy while the cheese melts quickly.
If your brisket is cold from the fridge, place it in a microwave-safe bowl with a splash of water or beef broth. Cover and heat for about 1 minute just to take the chill off. This ensures the meat is warm by the time the cheese is melted in the oven.
Spread half of the tortilla chips in an even layer on the prepared baking sheet. Sprinkle half of the cheddar and Monterey Jack cheese over the chips. Add a second layer with the remaining chips and the rest of the cheese. Layering helps prevent “naked” chips at the bottom.
Distribute the shredded brisket evenly over the top of the cheese. Scatter the black beans and jalapeños across the tray. Drizzle your favorite BBQ sauce in a zigzag pattern over the meat and cheese layers.
Place the baking sheet in the oven and bake for 10 to 12 minutes, or until the cheese is bubbly and starting to turn golden. Remove from the oven and immediately top with red onion, sour cream, avocado, and fresh cilantro. Serve hot and enjoy!