https://en.wikipedia.org/wiki/Mixed_economy Pretty much every country in the developed world falls fairly into this category. Including the United States itself.
Sanders identifies itself as the typical European socialist, of which there is a wide range. Hell most of the European center right is further to the left than Sanders is. I am saying this is as an American living in Europe.
Pegging Sanders to one of the half a dozen dysfunctional "socialist" states is disingenuous when he himself doesn't identify with those nations and when his political platform is simply an adaptation of a handful of socialist policies from other western Mixed Economies.