I remember when we were little being embarrassed that our nachos would consist of grated, melted cheese over homemade tortilla chips. Oh, how I wished were were rich enough to have Cheez Whiz or Velveeta to make nacho cheese sauce instead. The closest we ever came to a nacho cheese sauce is melting white Mexican cheese with green chile in a small sauce pan. The cheese would separate and get all grainy or gloppy and the whole thing would become oily instead of saucy.
I get a kick how things have changed and nachos made with grated, melted cheese is looked upon as authentic and the way to go, and nachos made with processed cheese sauce are held in a lower regard.