Preheat the air fryer to 400°F (200°C).
In a large pan over medium heat, brown the ground beef. Drain the fat and add ⅓ cup of water and the taco seasoning to the pan. Simmer for 5 minutes until the beef is fully seasoned.
Cut one of the tortillas into quarters. Heat the remaining four tortillas in the microwave for 20 seconds to make them more pliable and prevent cracking.
To assemble, place ¼ cup of the seasoned beef in the center of each tortilla. Layer with nacho cheese sauce, a tostada shell (or a handful of tortilla chips), sour cream, shredded lettuce, diced tomatoes, and shredded cheese.
Place a quartered piece of tortilla on top of the fillings and fold the edges of the larger tortilla around it to seal the wrap.
Brush the outside of the folded tortillas with vegetable oil. Place them seam side down in the air fryer basket.
Cook for 3-4 minutes or until the wrap is golden brown. Flip the wrap over and cook for another 3-4 minutes until both sides are crispy and browned.
Serve immediately and enjoy your crispy, delicious Air Fryer Crunchwrap Supreme!