NBC has stopped production of "The Nutt House," the new sitcom starring veteran actors Harvey Korman and Cloris Leachman. The first-year comedy series has been unable to hold a significant portion of the audience that tunes in to watch its lead-in, "Night Court," on Wednesday nights. NBC will air an extra episode of "My Two Dads" in the "Nutt House" time slot on Wednesday at 9:30 p.m. A full-time replacement was not immediately named.