Yoshomon, it strike me as a school debating club because words are twisted deliberately to suit the political point people are trying to make.I assume you agree that the people of America have a shared interest in not being hit by a nuclear bomb. Does this make you a nationalist? (A abusrd example i know but just to illustrate a point)
Saying 'all Americans have a shared interest in not dying' doesn't illustrate your point at all.
If I said, 'the oil/gas industry in the USA should be reorganized and nationalized to benefit people living in the USA', that's nationalist.
It's not something I want to get deep into right now, I was just making a brief note. Anyways I'll point out that I wasn't saying it was inevitable, only possible.
As far as how it could look, let's remember that Wal-Mart's reasons are to avoid having to pay healthcare costs of the workers. I also imagine that there would never be a complete nationalization, probably something closer to the government 'contracting' with Kaiser, or expanding medicare (in other words something like "single-payer insurance" which leaves the industry in the hands of the companies).
Kaiser et al. could maintain the insane prices of everything, charge it to the government, who then taxes workers more heavily. If it's in the form of national insurance, it would probably not cover quite a lot of things, and likely have all sorts of ways to gouge via deductibles, increase in rates, etc.
There could also be other problems such as having to go on a long waiting list for treatment (something that happens with many of the clinics in the Bay Area which receive government funding), etc.
Is that expanded enough?