Mexican Cheese Sauce? There's a Mexican restaurant in my hometown that serves (their term) 'Arroz con pollo'.  The dish itself seems incredibly simple -- it's pretty much just rice, chicken, and an incredible cheese sauce.

I've spent countless hours on google looking for a recipe for something resembling this sauce, but there doesn't seem to be one definitive version of arroz con pollo, so I haven't had much luck.

Can someone point me in the right direction?
That sounds like a standard queso cheese (typically found on your chimis etc.)

If you are looking for a terrific queso recipe, there are myriad. However, two tips for any queso: 


seek out "Chihuahua Cheese" (its a mild white that melts very smoothly and has a subtle flavor)
pepper and cumin and paprika roasted first are your friends, but if you add more than a little, they are your worst enemies. (also, fresh roast jalapenos for ideal flavor, don't use diced.)