Word is getting around that James Glassman, the executive vice president of U.S. News & World Report and president of the Atlantic Monthly, will be leaving both publications by the end of February. Glassman is the second top executive at U.S. News to leave this month. Two weeks ago, U.S. News Editor Shelby Coffey III left to become editor of the Dallas Times Herald. Like Coffey, Glassman reportedly has had differences with Mortimer B. Zuckerman, the Boston developer who owns the two magazines.

The 39-year-old Glassman, former publisher of The New Republic, was one of the first top executives Zuckerman hired when he bought U.S. News in 1984. Glassman is a contributing editor of The New Republic and writes frequently for Washingtonian. He reportedly will write a book. Zuckerman is still looking for an editor for U.S. News. Several sources say U.S. News Managing Editor Dave Gergen, a former aide to President Reagan, stands a good chance of getting the top job. 0f Riggins' Return

John Riggins had so much fun last year at the annual Salute to Congress Dinner that he thought he would go again. Never mind that he fell asleep on the floor during the stirring speeches, something few have been brave enough to do. And never mind that while seated at the table with the dour Supreme Court Justice Sandra Day O'Connor, he advised her to "loosen up, Sandy baby," something else few have been brave enough to do. All that aside, he'll be there tomorrow night at the Washington Press Club Foundation dinner in the Sheraton Washington hotel. O'Connor, however, will not be there this year. She, as they say, has another engagement. End Notes

It seems like a long way to go for a spinach and bacon salad. Braving yesterday's icy swirling snows, First Lady Nancy Reagan and her pal, columnist George Will, rode out to Shepherdstown, W. Va., to have lunch at the Yellow Brick Bank restaurant there. Will had the black bean soup and linguine with artichokes and sausage. The first lady had only the curried pumpkin soup and the salad. That must be some salad . . .

Ford's Theatre has sent out an invitation to a media reception Monday that reads, "Next to peace with the Soviet Union what the American people want most is . . . new chairs for Ford's Theatre." An exaggeration? Not completely to anyone who has sat in the authentic but uncomfortable chairs for longer than 10 minutes. House Speaker Tip O'Neill, Sen. Alan K. Simpson and satirist Mark Russell are scheduled to be at Ford's for the unveiling of a new chair Monday morning . . .

American Film Institute founder and chairman George Stevens Jr. was to be in New York City last night to receive a D.W. Griffith Award from the National Board of Review of Motion Pictures. He was to be presented with the Outstanding Contributor to the Motion Picture Industry award, being awarded for only the second time since it was created 77 years ago. Stevens was honored as founder of AFI, for his contributions to the industry and for the film tribute he made about his father the late George Stevens titled, "A Filmmaker's Journey." Among the other awards were best film for "The Color Purple"; best director, Akira Kurosawa for "Ran"; best actress, Whoopi Goldberg; best actor, shared by Raul Julia and William Hurt; best supporting actress, Anjelica Huston; best supporting actor, Klaus Maria Brandauer; and best foreign film, "Ran" . . .

Rep. Harley Staggers was married Saturday to Lesley Sergy, a former West Virginia University basketball player. Staggers, 34, who will seek a third term, met Sergy, 30, when they were both attending WVU. Sergy works in sales for the Burroughs Corp. It is the first marriage for both . . .

Former president Richard Nixon, 73, has been hospitalized in Miami. Nixon, who had been vacationing in the Bahamas, stopped at the Miami Heart Institute for a checkup and was admitted for a viral infection and dehydration. Dr. Lewis Elias, lac fix Nixon's physician in the Miami area, diagnosed the former president as having "just the flu." The hospital listed his condition as satisfactory . . .

Rocky/Rambo Sylvester Stallone and Oscar winner Sally Field have been named man and woman of the year by The Hasty Pudding Theatricals group at Harvard University . . .

Haing S. Ngor, the Cambodian doctor who won an Oscar for his role in "The Killing Fields," has returned to the Thai-Cambodian border to make a documentary about the suffering of his people . . .