Heat oven to 200° C.

Put a large sauté pan with high sides over medium-high heat and add the bacon. Cook, stirring occasionally, until the fat has rendered and the pieces are crisp, about 5 to 7 minutes, then remove the bacon and set aside.

Add the onions to the bacon fat and sauté, stirring occasionally, until they have softened and started to go brown around the edges, about 3 to 5 minutes.

Add the ground beef and garlic and cook, breaking up the meat with a spoon, until browned, about 5 minutes.

Add the chile powder, cumin, salt, paprika, black pepper, sugar, cornstarch and red pepper flakes and stir to combine and toast the spices.

Add enough chicken stock or water to loosen the mixture, and allow it to simmer, uncovered, until the sauce is slightly thickened, about 5 to 6 minutes. (Add a little more stock or water if mixture is too thick.)

Assemble the nachos on a half sheet pan:

Put a layer of tortilla chips on the pan and cover with about 1/3 of the meat sauce, then add about 1/3 of the lettuce, 1/3 of the jalapeños, some avocado slices and a handful of the Monterey Jack and Cheddar cheeses. Top with more tortilla chips, more meat sauce, more lettuce, jalapeños, avocado and cheese, then make a final layer of chips, meat, bacon, jalapeños, avocado and cheese. Top with crumbled Cotija cheese and slide the sheet pan into the oven to bake until the cheeses have melted through, about 10 to 12 minutes.

Top cooked nachos with the sliced radishes and tomatoes, and dot the tray with teaspoons of sour cream. Scatter the cilantro over the top and serve, accompanied by limes and hot sauce.