01 - Set the oven to 400°F and allow it to heat fully before proceeding.
02 - Warm olive oil in a large skillet over medium heat; add chopped onion and garlic, cooking until softened, about 2 minutes.
03 - Add ground beef to the skillet; break it apart and cook until evenly browned, approximately 5 to 6 minutes.
04 - Incorporate cumin, smoked paprika, chili powder, salt, black pepper, and tomato paste into the meat; stir and cook for an additional 1 to 2 minutes, then remove from heat.
05 - Spread tortilla chips evenly across a large baking tray or ovenproof dish.
06 - Distribute the seasoned beef over the chips, then evenly sprinkle shredded cheddar and Monterey Jack cheeses on top.
07 - Scatter diced tomato, jalapeño slices, and black olives over the cheese if using.
08 - Place the assembled nachos in the oven and bake for 8 to 10 minutes, until the cheese is fully melted and bubbly.
09 - While the nachos bake, mash avocados in a bowl with lime juice. Fold in diced tomato, red onion, cilantro, salt, and pepper until combined.
10 - Remove nachos from the oven, sprinkle with additional chopped cilantro, and serve immediately alongside or atop the guacamole.