You'll be seeing less of him on the air, but Nightline anchor Ted Koppel has re-upped for five more years. Starting in January, Koppel will make a Carson-like cutback from four to three nights a week on the late-night news program, which was conceived 20 years ago to update viewers nightly on the Iran hostage crisis. Koppel wants to do more work on the program's Web endeavors and let ABC have more airtime to nuture an eventual successor. Also re-upping is Tom Bettag, Nightline's long-time executive producer. But he'll step back from producing the nightly show. Instead, he'll produce Koppel's multi-part specials and occasional prime time shows. Stepping up to produce the nightly broadcast is Leroy Sievers, who will report to Bettag.