Some $91 million is spent cleaning up litter in Louisiana every year, according to Lt. Gov. Billy Nungesser, who highlighted a eight-parish regional summit on litter Monday at LSUE. “I remember the president of Nissan Motors stood up at a press conference 30 years ago before I was in politics, and he said, ‘We decided we’re going to build our plant in Jackson, Mississippi, instead of New Orleans E…