CBS is expanding its unscripted lineup with three new series, including a reboot of “Undercover Boss” hosted by Drew Carey. The show returns for its 12th season, with corporate executives going undercover inside their own companies to get a firsthand look at employees and operations. CBS also ordered “Stacks of Cash,” a game show hosted by Mike O’Malley, where six contestants answer questions to earn oddly shaped blocks and stack them toward a gold line. One wrong move can send the whole pile crashing down. The series was filmed in Portugal. The third show, “24 Hour Millionaire,” comes from the executive producers of Big Brother. Contestants will compete in nonstop strategy and physical challenges for 24 straight hours, with one player guaranteed to win $1 million. No breaks, no sleep and apparently no regard for anyone’s need to function normally the next morning. CBS says premiere dates and additional details will be announced later.