Nevada sports books could find themselves on the losing side of Sunday's Super Bowl. Though final figures won't be released by state gaming regulators until later this week, Nevada casinos are expected to exceed last year's wagering handle of $81.5 million. But few expect Sunday's game to reach the record $94.5 million in wagers on the 2006 Super Bowl. One bright spot is likely to be visitor volume. The Convention and Visitors Authority estimates 278,000 football fans visited Las Vegas this past weekend, up nearly 14% from last year's Super Bowl weekend.