In a small bowl, combine the minced jalapeño pepper, scallions, garlic, cilantro, salt, lime juice, and diced tomatoes. Stir well to combine, set aside, and let the flavors meld while you prepare the beef.

Heat the vegetable oil in a medium skillet over medium heat. Add the finely chopped onion and sauté until softened, about 3 minutes.

Introduce the minced garlic, cooking for an additional minute without letting it brown.

Once fragrant, add the lean ground beef along with chili powder, oregano, cumin, cayenne pepper, salt, and tomato paste. Increase the heat to medium-high, breaking up the meat with a wooden spoon until it is no longer pink, approximately 4 to 5 minutes.

Set your oven to 400°F (205°C) and position a rack in the middle. Prepare a rimmed baking sheet by lining it with parchment paper for easy cleanup.

Spread half of the tortilla chips in an even layer on the baking sheet.

Top with half of the cooked beef mixture and sprinkle half of the shredded cheese over the top. If desired, add half of the jalapeño slices for extra kick.

Repeat the layering process with the remaining chips, beef, cheese, and jalapeños.

Place the baking sheet in the preheated oven and bake until the cheese is beautifully melted and bubbly, about 7 to 10 minutes.

Once baked, remove the nachos from the oven and serve directly on the sheet with the prepared salsa and optional garnishes like lime wedges, sour cream, and guacamole.