There has been a trend of Hispanics moving to the upper midwest, but not necessarily large cities.
Why? Well, for instance there's a small town north of where I live Arcadia, Wisconsin, that has been known for it's poultry production.
The problem: many of the young residents of the area don't want to work in the nasty poultry factories anymore. Fowl...er... foul conditions. I used to work with a guy from the area who told me about working in those factories..
But Hispanics will do those jobs.
So now Arcadia has a sizable Hispanic population. Drive through the town, and you'll see a number of businesses that cater to Hispanics.
There are a number of other small towns in Minnesota and Wisconsin the wife and I have driven through where we noticed large crowds of people of obvious Hispanic descent. They're willing to work in the food production plants where the native residents don't want to work.