Drake said Reagan was doing well and would stay the night in the same room where former President Ronald Reagan stayed after he broke his hip at home in 2001. He died June 5, 2004.
The former first lady is "joking and visiting in her room," Drake said.
Reagan's family physician recommended the overnight stay "as a precaution," Drake said.
Nancy Reagan's last major public appearance was at the Jan. 30 Republican presidential debate at the Reagan Library in Simi Valley, Calif., where she sat with Gov. Arnold Schwarzenegger.