Sorry to join in so late, but I can't let the Cuban nachos go without comment.
In Cuba, or Florida for that matter, "nacho" has one meaning: the diminutive of the name Ignacio. When I was a kid in 80's Tampa, the bad, short-lived SoCal chain Nogales opened up some shops there (this was pre-Taco Bell for most of Florida, BTW). Some marketing genius thought that SoFla was the perfect place to start east coast expansion because of the many "hispanics." They didn't realize that fast food Mexican would have zero resonance with the notoriously culturally conservative Florida Cubans who wouldn't know a taco from a chapulin.
Anyway, to his credit or discredit, the LaGuardias may well have invented this "Latin Fusion" item, as it has been on the menu as long as the restaurant has been around. The fusion of Cuban and Mexican, in my experience, is a particularly Chicago phenomenon and one that usually does a disservice to both cuisines. Cafe 28, the most obviously Mexican/Cuban restaurant, mostly keeps the foods separate.
There is a lot of pressure on non-Mexican Latin restaurants to provide familiar Mexican dishes to the mostly non-Mexican patrons who "expect" to see certain things on the menu. (In my experience, Mexicans generally don't go looking for Mexican at Cuban, Argentine or Colombian restos; why would they?) Thus, many Cuban, Colombian, Ecuadoran, and Guatemalan places here include explicitly Mexican menu items, sometimes under headings like "Platillos Mexicanos," sometimes not. In the latter case, this can lead to confusion and misinformation. This happens between other cuisines as well. (A major newspaper food critic last year described arepas as typically Cuban.)
The best example of this trend, for me, is the much-loved Irazu. This Costa Rican restaurant serves mostly Americanized Mexican food that is more like something from San Francisco, CA than San Jose, CR. In this case, that's for the better, as CR food is notoriously boring, esp. compared to that of its Central American neighbors. But I assure you, veggie burritos as big as your head are not Costa Rican staples.
Similarly, I was at the underappreciated Venezuelan place, Caracas, when a non-Latin customer just wanted a burrito. The owner, sadly in my opinion, sent someone out to fetch some big tortillas to keep the guest.
Finally, I have noticed that HP Puerto Rican places are the exception to the creeping gringo-Mex problem. You almost never see any non-Puerto Rican menu items there. This is likely a result of the large, compact and culturally proud PR community that has always maintained a distinct profile in Chicago, and has achieved a disproportionate (in terms of population numbers vis a vis Mexican and other distinct ethnic groups) share of the political pie here.
But I digress. The "nachos" made with tostones (poor examples of tostones at that) are probably not a concession so much as an attempt at something new. But I think they are awful.