Allow cheeses and butter to stand at room temperature until soft.
Place Cheddar, cream cheese, blue cheese, and butter in a large bowl; with an electric mixer, beat until blended.
Add garlic and beat until creamy.
Cover and chill mixture until firm enough to shape into balls, but not hard (about 2 hours).
Divide in half and shape each half into a smooth ball.
Sprinkle nuts on a piece of wax paper and roll each ball in about half of the nuts, pressing in lightly.
Place balls in separate plastic bags and seal; refrigerate or freeze until needed.
Before serving, allow cheese balls to stand at room temperature, unwrapped, for 30 minutes if refrigerated, or for 3 to 4 hours if frozen