Sprinkle half the cheese evenly over the chips, layer with the ground beef, and top with the remaining cheese. Place under the broiler until cheese is melted, about 2 minutes. Evenly top the nachos with chopped tomato, thinly sliced scallions, black olive slices, pickled jalapeno slices, and chopped avocado.
Bake in the preheated oven for 20 minutes. Remove the foil and bake for 5 more minutes. Remove from the oven and transfer nachos to a platter. Top with shredded lettuce and remaining beans, jalapeno peppers, and pico de gallo. Stir sour cream with just enough water to thin slightly; drizzle over the nachos.
Evenly top the nachos with chopped tomato, thinly sliced scallions, black olive slices, pickled jalapeno slices, and chopped avocado. Create a mound of ¼ cup sour cream in a central location on the sheet pan and serve while warm.
Remove from the oven and transfer nachos to a platter. Top with shredded lettuce and remaining beans, jalapeno peppers, and pico de gallo. Stir sour cream with just enough water to thin slightly; drizzle over the nachos. Drizzle remaining queso blanco over top and sprinkle with scallions.