6. Stir in the sour cream.
7. Add salt to taste.

Notes: You can vary which chiles you use to control how hot you want the queso to be. Also, if the sauce is too thick, feel free to add a bit more milk a tablespoon at a time. The key, however, to a smooth sauce is adding the cheese very slowly and not adding any more cheese until the previous addition is completely integrated into the sauce.