Heat a large skillet over medium-high heat. Add the diced onion and cook for 2-3 minutes until softened and fragrant. Add minced garlic and cook for another 30 seconds, stirring constantly to prevent burning and to release the aromatic garlic oils.

Add the ground beef to the skillet, breaking it up with a spoon as it cooks. Continue cooking for 6-8 minutes until the beef is completely cooked through and lightly browned. Drain any excess fat if needed, leaving just a light coating for flavor.

Stir the chili powder, cumin, paprika, and cayenne pepper into the beef mixture. Cook for 1-2 minutes while stirring constantly so the spices bloom and coat every piece of ground beef evenly. This step transforms ordinary beef into the seasoned foundation for your cheesy loaded beef nachos.

Arrange tortilla chips in a single layer on a large baking sheet or oven-safe platter. Spread the warm seasoned beef evenly over the chips, then sprinkle the cheddar and Monterey Jack cheeses generously over top. Working quickly ensures the beef stays warm and helps the cheese melt faster.

Broil the loaded chips at 450°F for 3-4 minutes until the cheese melts completely and starts to bubble around the edges. Watch carefully to prevent burning—cheese can go from perfectly melted to scorched in seconds under the broiler's intense heat.

Remove from the broiler and immediately top with dollops of sour cream, salsa, diced tomatoes, jalapeño slices, and fresh cilantro. Drizzle everything with lime juice just before serving to add brightness and prevent the fresh toppings from wilting into the warm cheese.