Preheat the oven to 375°F (190°C) while you prepare the ingredients. Cut the tortillas into triangles and place them on a baking sheet lined with parchment paper. Lightly brush them with the teaspoon of olive oil and bake for 8 to 10 minutes, or until golden and crispy. Remove from the oven and set aside.

In a nonstick skillet over medium-high heat, cook the ground beef with a pinch of salt and pepper. No additional oil is needed. Cook for 6 to 8 minutes, breaking it up with a wooden spoon, until fully browned. Once done, remove from the heat and let it rest for a few minutes so any excess moisture evaporates.

Prepare the fresh toppings. Make sure the tomato is seeded and well drained to avoid soggy nachos. Do the same with the onion.

On a baking tray, arrange the toasted tortilla chips to form a base. Layer the warm (not hot) beef over the chips, then sprinkle the shredded cheese. Add the diced tomato, chopped onion, and sliced jalapeños if using. Finally, spoon small dollops of Greek yogurt on top.

Bake in the preheated oven for 8 to 10 minutes, just until the cheese is melted and the tortilla edges look golden. Serve immediately, as the moisture from the toppings can quickly soften the chips.