Preheat your oven to 375°F (190°C).
Heat a large skillet over medium heat.
Add the ground beef and cook until browned, breaking it apart as it cooks (about 5–6 minutes).
Drain excess grease if needed.
Stir in the diced onion and garlic. Cook for 2–3 minutes.
Add chili powder, cumin, salt, and black pepper. Stir well and remove from heat.
Spread tortilla chips in an even layer on a baking sheet.
Sprinkle half of the cheese over the chips.
Spoon the beef mixture evenly over the cheese.
Add the remaining cheese on top.
Bake for 8–10 minutes, or until the cheese is fully melted.
Remove from the oven and top with diced tomatoes, jalapeños, green onions, sour cream, and guacamole.
Serve immediately.