Several years ago, a guy in one of my homebrew clubs, who generally makes some wacky beers, made a salsa beer. It's always been a memorable beer to me because it was at either the first or second homebrew club meeting I had been to. I know that he made it with some peppers, tomatoes and (i think) onion from his garden.
I wouldn't add pre-made salsa or chips to the beer. Good corn tortilla chips should be nothing but corn, oil and salt. Good salsa is nothing but vegetables. I'd start with a cream ale, maybe increase the flaked corn. Keep the hops low, they'll compete with the other flavors. Then add tomatoes and peppers to the secondary. Maybe also some lime, cilantro, and salt.
The power of suggestion is a big part of these types of novelty beers. As long as you get tomato, and a hint of corn and peppers, people's minds will fill in some of the other blanks when you tell them it's a chips and salsa beer.