Before I moved I went to a restaurant called Nachos. They of course served the best Nachos! They had this thin sweet vinegar tomato type sauce that they poured over them. I have searched and searched for some kind of recipe like this. I usually end up finding recipes for vinegar hot sauce or an enchilada sauce.
I know the chances of anybody knowing what I am talking about are slim but any helpful suggestions are helpful! Thanks

Nacho's Restaurant, Eugene OR (http://nachosrestaurant.com/)

I found this link if you want to contact them. I don't know if it is the same place, but many restaurants will be happy to share ingredients with happy customers.

Good Luck.

Please let me know if you get a good answer from them??