Place your heavy skillet over medium-high heat. Add the ground beef, breaking it apart with a wooden spoon as it cooks. Cook for 5 to 6 minutes until completely browned and the internal temperature reaches 160°F (71°C). Drain off excess grease. Stir in the taco seasoning and water. Simmer for 2 minutes until the liquid reduces and coats the meat. Remove from heat and set aside to cool slightly.

Preheat your oven to 400°F (204°C) and line a large rimmed baking sheet with aluminum foil. Arrange half of the tortilla chips in a flat, overlapping single layer across the pan. Pop the bare chips into the oven for exactly 3 minutes. Heating the chips first releases their natural corn oils and crisps the starch grid, preparing them for the heavy toppings.

Remove the hot pan from the oven. Immediately sprinkle half of your freshly grated Cheddar and Monterey Jack cheese directly onto the hot chips. This creates a melt-zone that blocks moisture from entering the porous chip surface. Evenly distribute half of the seasoned ground beef and dried black beans over this base cheese layer.

Layer the remaining tortilla chips directly over the first layer. Top these chips with the rest of the ground beef, black beans, and the remaining half of the grated cheese. Ensure the cheese is scattered well across the top to act as a final blanket for the ingredients below.

Return the loaded sheet pan to the oven at 400°F (204°C). Bake for 5 to 7 minutes until the cheese is completely melted, bubbling, and forming beautiful golden brown spots around the edges. Watch closely to prevent the exposed edges of the chips from burning.

Remove the bubbling nachos from the oven. Let them rest for 2 minutes so the cheese structure stabilizes. Scatter the diced tomatoes, red onions, pickled jalapeños, and fresh avocado cubes evenly across the hot cheese. Garnish with dollops of cool sour cream and chopped cilantro. Serve directly from the sheet pan immediately.