Preheat the oven to 400°F (200°C).
Place about half of the tortilla chips in a cast iron skillet or on a large rimmed baking sheet to form an even layer.
Sprinkle half of the shredded cheddar and half of the shredded pepper jack evenly over the chips.
Scatter half of the rinsed and drained black beans over the cheese layer.
Add the remaining chips on top, then layer with the remaining cheddar, pepper jack, and black beans.
Bake in the preheated oven for 10–15 minutes, until the cheese is fully melted and bubbly.
Remove from the oven and sprinkle the Queso Fresco or Cotija over the hot nachos.
Add any optional toppings you like such as diced tomatoes, black olives, chopped avocado, cilantro, sliced jalapeño, chopped green onion, and sour cream.
Serve the nachos warm.
Note: If you don't have a cast iron skillet, use a large rimmed baking sheet instead.