LOS ANGELES -- Paul Friedman, tabbed a decade ago as the Wunderkind of NBC News, has been named executive producer of "ABC World News Tonight With Peter Jennings."

He replaces William Lord, who's been in the "World News Tonight" hot seat since April 1984. No decision about Lord's next assignment has been announced.

Friedman, 42, joined ABC News in 1982 after his steady rise at NBC News had been stopped in its tracks by then-NBC News president William Small. At the time, Friedman was producing an NBC News magazine show that had been anchored by David Brinkley and had had the misfortune of being scheduled against a then-fresh CBS phenomenon named "Dallas."

Small, previously a CBS News executive, and Brinkley were already on a collision course, which finally resulted in the veteran anchor's departure for ABC. Friedman, who had been a favorite of Les Crystal, Small's predecessor at the top of NBC News, soon followed.

Friedman's departure in 1982 ended what had been a promising career at NBC News, which had begun in radio in 1967 and had been foreshadowed ironically enough when he wrote a thesis on top management at NBC News while still at the Columbia University School of Journalism.

In 1968, Friedman had become a TV reporter at WRC in Washington, where he proceeded to do well on assignments with the Poor People's Campaign, the education beat and investigative reporting; his series on the perils of cyclamates brought about changes in the law.

Promoted to New York, Friedman began the two-hour evening news shows in that market as an executive producer at WNBC. This earned him a promotion to executive producer of the "Today" show. After 3 1/2 years in that job he was named executive producer of "Prime Time Sunday" and its several variations starring Tom Snyder and then Brinkley.

On joining ABC, Friedman was dispatched to the London bureau (his wife Gillian is British) where he prospered, producing broadcasts for Jennings when the latter was in London as chief overseas correspondent for the network.

In the spring of 1987, Friedman was brought to New York for a period to aid Jennings and ABC News management in making long-range plans for "World News Tonight," a move that obviously figured in this week's promotion.

Jennings said yesterday, "It's a good move. I am terribly pleased. Paul has been around for a long time, he's been up and he's been down and that makes a mature man. The program needs a good mature hand that can step back and take a look; someone who can say, 'Let's poke into the corners' with the broadcast.

"We were in the London bureau together and I enjoyed the experience. We liked the way each other thought. I think viewers will see a difference in the broadcast over the long run and I expect we'll strengthen the staff."

Jennings had praise for Lord and minimized any differences with his former executive producer as they had been spelled out rather strongly in a recent profile in New York magazine.

"Sure we differed on some things, but Bill's a really good line producer," Jennings said. "I think it's rather amazing he could do the very, very tough job for four years. I certainly hope ABC News will find a way to use his extraordinary talents."

Friedman, who was house-hunting yesterday in Scarsdale, said he plans to stay only three years on the job, "and I've begun counting the time already."

The new executive producer recalled that when Brinkley congratulated him on the move to ABC in 1982 the anchor had warned him, "They make you work over here." Also in the News

Fox Broadcasting announced yesterday that starting March 6, it will air "It's Garry Shandling's Show" in the 9 p.m. Sunday time slot.

The program will also continue to air on the Showtime cable network.

The Fox-owned stations, including Channel 5 in Washington, are scheduled to move their Sunday night newscasts to a 10:30 start on March 6 when Fox slides "Duet" and "The Tracey Ullman Show" up a half hour with the addition of the Shandling program to its schedule.

Fox is also developing another half-hour show for the 9 to 11 p.m. Sunday lineup by next fall, to make a tougher fight of it against network movies in that time slot.

At a meeting of Fox affiliates here yesterday, station executives also learned that Aaron Spelling, no longer bound by an exclusive contract to ABC Entertainment, is developing a series for Fox "starring young attractive women." Spelling said the new series could be ready for the Saturday lineup in the fall or perhaps for a place in a third night of primetime programming if Fox develops it.

Fox also announced it has given a 13-episode commitment to Stephen Cannell Productions for a companion series to his "21 Jump Street" that would follow "Jump Street" cases through the legal system with frequent appearances on the new series by "Jump Street" stars. Working title of the new series: "Return of the Prince." The new series will be launched with a special two-hour "21 Jump Street" later in the year. By the fall it could eventually land on Sunday night right after "Jump Street."

RATING SHARE NETWORK 1......28.3.....Seahawks/Oilers Overrun.......43.....NBC 2......25.4.....The Golden Girls..............42.....NBC 3......25.2.....Murder, She Wrote.............35.....CBS 4......22.5.....Rose Bowl Game................36.....NBC 5......22.0.....60 Minutes....................32.....CBS 6......21.2.....Once Upon a Texas Train.......32.....CBS 7......20.8.....Orange Bowl Game..............35.....NBC 8......19.8.....The Cosby Show................37.....NBC 9......19.6.....Amen..........................34.....NBC 10.....19.5.....My Two Duds...................28.....NBC 11.....19.4.....Family Ties...................27.....NBC 12.....18.8.....227...........................31.....NBC 13.....18.5.....Growing Pains.................29.....ABC 14.....18.4.....Who's the Boss?...............29.....ABC 15.....18.3.....An Officer and a Gentleman....32.....NBC 16.....17.5.....A Different World.............34.....NBC .......17.5.....Scared Sexless................30.....NBC .......17.5.....Matlock.......................28.....NBC .......17.5.....Unsolved Mysteries............28.....NBC 20.....17.0.....Roman Holiday.................28.....NBC

NBC celebrated the New Year's weekend with its biggest ratings win this season, thanks to high-rated holiday football games. The network scored an overall 17.6 rating and 29 share to CBS' 12.7/21 and ABC's 11.5/19. It was NBC's 10th weekly victory in a row.

The No. 1-rated show of the week was the National Football League playoff game between Houston and Seattle, which ran 37 minutes into primetime Sunday and got a 28.3/43. NBC also scored with the Michigan State-USC Rose Bowl game, which ran 30 minutes into primetime on New Year's Day and came in fourth, and the primetime Orange Bowl matchup between Oklahoma and Miami later that evening, which was No. 7.

Football games are counted in the ratings if they run over into primetime by 15 minutes or more.

NBC's "Scared Sexless," a documentary about AIDS and social mores, ranked 16th with a 17.5/30, the highest rating for an NBC News documentary since 1977.

NBC's "Cosby Show" rerun failed to reach its customary first place on New Year's Eve, but the network's "My Two Duds" on Sunday was in the top 10 for the first time. Overall NBC had 15 of the top 20 shows.

"CBS Evening News," which aired all five days last week, continued its winning streak with an average rating of 12.8/22. ABC's "World News Tonight" was second with an 11.7/21, and "NBC Nightly News" was third with an 11.2/20. Both aired only Monday through Thursday because of football on Friday.