Are any corn products in the United States made from nixtamalized corn? I believe polenta, corn meal, grits, and corn flour are not. But how about tortilla corn chips you buy at the supermarket? This is what I am looking for!
I have a link to a quora question that I believe is wrong in that it says most corn products in the United States are but I read just the opposite on other sources.
Still searching, this is a tough question.  Here is the link which gives various opinions. https://www.quora.com/Why-isn-t-nixtamalization-a-standard-process-for-corn-production-outside-of-Central-or-South-America-European-settlers-seem-to-have-just-ignored-and-eliminated-the-process
P.S. After posting this I discovered a corn chip made with mesa flour! It's called Calidad. It's the only one so I assume the quora answer is incorrect. If it does not list as mesa flour probably the corn meal is not nixtamalized.
Masa Harina is nixtamalized corn flour, as is anything made from it.  So, most corn tortillas you can buy are, as are premade tamales, sopes, etc.  While you may come across varieties made from non-treated corn flour (be suspicious of anything bright yellow), most are treated.  Corn/tortilla chips are a little bit more of a mixed bag; some are made from corn flour and some from masa, and it's pretty hard to tell from the labeling which is which.
Hominy is also nixtamalized, as are grits, and any product made from/with grits (no, grits and polenta are not the same thing).  There's another kind of masa, called masarepa, which is used to make arepas.  This isn't an exhaustive list, but should be sufficient to show that yes, we are eating nixtamalized corn in the United States.