WHAAAAAAA Once you try making nachos in a cast-iron skillet, you may never go back to using a cookie sheet. The cheese gets crispy around the edges, and the skillet retains the oven's heat to help keep the nachos melty and delicious all the way through.
The Best Nachos Ever (pulled pork, green chilies and cheese nachos)
How to Make Nachos for a Crowd — Alton Brown, "The key to these nachos is using aluminum foil to make spacers for separating the racks so that maximum meltage is attained. The other thing: fresh orega (How To Make Nacho Cheese)