Is there anywhere in the U.S. where I can buy Chilean queso fresco?

No, because in Mexico & Chile, queso fresco is often a raw milk cheese, but in the United States the cheese is made from pasteurized milk, due to concerns about bacteria in raw milk. You can buy Queso Fresco in the USA, particularly are grocery stores that cater to the Hispanic residents in your area, assuming that there are a lot of them where you live. Any grocery store can advise you if they carry it, or if they are able to order it for you.

Source: http://www.wisegeek.com/what-is-queso-fresco.htm

Here is where you can order some, via online/mailorder:

http://www.gourmet-food.com/gourmet-cheese/ranchero-queso-fresco-cheese-103191.aspx

¡Buena suerte!