Begin by finely dicing your small onion into pieces roughly the size of a pea. Heat one tablespoon of olive oil in a large skillet over medium heat for about one minute until you can smell the oil warming. Add your diced onion to the hot oil and stir occasionally as it cooks. You're looking for the onion to become soft and translucent, which takes approximately five minutes. You'll notice the pieces transform from opaque white to glassy and slightly golden at the edges. This is the perfect moment to move forward—don't let it brown too much, as we want sweetness rather than caramelization here.

Grab your can of black beans and pour the entire contents—including all the liquid—directly into your skillet with the cooked onions. Do not drain or rinse the beans. That starchy liquid is liquid gold for creating a cohesive sauce that binds everything together. Next, add your ten-ounce can of diced tomatoes with green chiles, again using the entire can including the juice. Sprinkle in your 1/2 teaspoon chipotle powder, 1/2 teaspoon ground cumin, 1/4 teaspoon garlic powder, and 1/4 teaspoon salt. Stir everything together thoroughly, making sure the spices distribute evenly. Let this mixture simmer over medium heat for approximately ten minutes, stirring occasionally. You'll know it's ready when the liquid reduces significantly and no longer pools on the bottom of the skillet. The mixture should be thick and clingy, almost like a thick stew rather than soup.

While your bean mixture simmers, preheat your oven to 350 degrees Fahrenheit. This moderate temperature melts the cheese perfectly without burning the chip edges. Now prep all your toppings so everything is ready when you need it. Shred your four ounces of cheddar cheese (use the large holes on a box grater if shredding fresh). Finely dice your Roma tomato, removing some of the seeds to prevent the nachos from becoming soggy. Thinly slice your jalapeño. Roughly chop your fresh cilantro. These prep steps take about five minutes total and make assembly stress-free.

Line a standard baking sheet with parchment paper or aluminum foil for easy cleanup. Spread your eight ounces of sturdy tortilla chips in a single layer across the baking sheet, trying to minimize overlapping. Overlapped chips don't get crispy and don't hold toppings well, so take a moment here to arrange them nicely. Spoon approximately half of your bean mixture over the chips, distributing it as evenly as possible. You want beans on most chips, but you don't need to be perfect here. Sprinkle half of your shredded cheddar cheese over the beans. Now repeat: another layer of chips, another layer of bean mixture, and the remaining cheese on top.

Transfer your assembled nachos to the preheated 350-degree oven. Bake for five to seven minutes, watching carefully as you approach the end. You're looking for the cheese to be completely melted and bubbly, with the chip edges just beginning to turn a light golden brown color. Do not overbake—even one extra minute can make chips tough and bitter. The moment you see that golden color appearing, remove the nachos from the oven. They'll continue cooking slightly from residual heat, so removing them early prevents that crispy-turning-to-stale transition.

Remove the baking sheet from the oven and place it on a trivet or cooling rack. Immediately drizzle or dollop your sour cream over the top of the hot nachos. The warmth will slightly soften the sour cream, creating wonderful flavor pockets throughout. Now add your fresh toppings: scatter the diced Roma tomato, sliced jalapeño, pickled red onions, and chopped cilantro evenly across the nachos. These fresh elements provide brightness, acidity, and texture that contrast beautifully with the warm, creamy, savory base. Serve immediately while the nachos are still warm and the chips are at their crispiest. This dish doesn't hold well after more than about five minutes, so gather your guests before plating.