Nachos: what came first, the dish or the chile slice?

I'm trying to have one of those ah-hah moments but it still isn't quite clear. 

What comes to mind when you think of the word nacho? If you're like me, you think of that appetizer dish served at Mexican restaurants; of tortilla chips with melted cheese and slices of jalapeño chile peppers on top. Well, we're not alone, most English dictionaries have that definition for nachos as well. Even the Spanish language dictionaries include that meaning of nachos, although many online references are translations of English search engines. Only the Real Academia Española dictionary has a different definition of nacho, as in a "flat nose" like that referred to with the word chato: nacho, cha. (Del lat. nasus, nariz). 1. adj. rur. Ast. chato (‖ de nariz poco prominente). U. t. c. s. Which brings me to the reason why I ask this question anyways.

On Saturday I decided to make a pizza but we were out and we were missing some essential toppings at home, and so on our way home I asked Margo to stop off at the convenience store to pick up a couple things. It was late and I'd be making it while putting the baby to bed so I broke down and got a few canned things—sliced jalapeños and mushrooms. In the canned food aisle, chiles come in many presentations. Whole, pureed in salsa, diced in salsa, rajas, and, NACHOS. Here's where I got confused. I always thought of nachos as the above appetizer. Here the can was saying "nachos de chiles," in other words, referring to the nachos as a type of crosswise-sliced chile. As opposed to rajas, which are sliced longish and lengthwise.

Now I'm pretty sure that nachos without sliced chiles probably isn't an authentic dish (forget the movie theatre version). So next time you order that dish, just know that if it doesn't include the chiles, it ain't the real thing. But I got to wondering if maybe this cut of chile, the one that's most often used for the appetizer, is how the dish got its name, or if it's the other way around. I wasn't able to find much clarification online. I think a Spanish language scholar, or ethnoculinarist of Mexican food is my only hope at this point. 

In any case, the nacho-sliced  jalapeños tasted just the same as the whole or the rajas, which is to say "bien picante."  The pizza was a hit.