Warm all eight flour tortillas for 20 seconds so they bend without cracking.
Spread 1/4 cup nacho cheese in the center of each large tortilla and add 1/2 cup hot beef at 165°F.
Set one tostada over the beef and top it with sour cream, lettuce, tomato and cheddar.
Place one small tortilla over each stack and pleat the large tortilla edges tightly toward the center.
Heat the oil in a skillet over medium heat and cook each crunchwrap seam-side down for 2 to 3 minutes.
Flip and cook for 2 minutes until both sides are golden and the fold holds.