The appointment was anticipated and sets up a political scramble on how Heller’s House seat will be filled. State law says a special election must be held within 180 days of a vacancy.
Ensign has been dogged by an ethics investigation and announced last week he was resigning effective May 3.
Heller last month said he would run for Ensign’s seat in 2012, and Sandoval quickly endorsed him.
In a statement, Sandoval said Heller “is an experienced representative who is ready for the responsibilities of this office, and who will work hard, not just for Nevada, but for the entire nation.”