In New Mexico (southwestern US state) the McDonalds all have a large pot of green chile sauce. It's roasted green peppers diced up with onion and sauted, then some cumin and a bit of flour to thicken it with chicken broth as a base. I lived there years ago but still fill my freezer with roasted green chile peppers every fall so I can make the stuff. It goes on about half the food in New Mexico (the other half being topped with the smokier cousin - red chile!)