Nachos are a delicious concoction made by Sheogorath while he was in Mexico. He decided eating chips and salsa wasn't "good enough", and opted for his favorite food instead: cheese. Sheogorath likes to put cheese on everything, but it's usually really gross. But when he put cheese on chips, Everybody liked it and forgave Sheogorath for the seven murders he committed while creating the dish.
Nachos are cited to have three main uses. The first, obviously, is to chuck them at people you don't like. The second is to eat them. The third it to pretend they are pieces of the Triforce. As you can see, nachos are incredible things that should not be taken lightly. If you choose to take them lightly, Sheogorath might kick you in the shin.