Washington seeress Jeane Dixon's office confirms that she is officially the "spiritual adviser" on the movie "Inchon," which is being produced in South Korea by an affiliate of Rev. Sun Myung Moon's Unification Church. But a spokesman declines to explain exactly what that means and whether it is a paying job.

Multimillionaire builder Nathan Landow, who was quoted on CBS last week as saying that Hamilton Jordan didn't use drugs in California on Oct. 21, 1977, isn't the only member of his family loyal to the Carter administration. Landow, one of Jordan's closest buddies, has a daughter working on the White House staff. Harolyn Sue Landow, 23, was hired there last fall and is a special assistant to Jordan's deputy, Stephen Selig . . .

Criminal lawyers like Edward Bennett Williams and William Hundley may not have time to read pop fiction like Sidney Sheldon's "Bloodline." But they had better caution their wives and secretaries not to be giving unauthorized interviews. Sheldon's new book is going to be about a lawyer just like them, and he has been quietly and busily researching the Washington background . . . President Carter's mother, Miss Lillian, has her own little feud going with one small voice of the media. She is mad at The Plains Monitor for describing her standing at the train depot recently in tennis shoes and a yellow polyester pantsuit, "looking like an octogenarian daffodil" . . . The Internal Revenue Service didn't throw rice, but agents are crying now that one-time Washington gambling kingpin Joe Nesline married his longtime girlfriend, Becky, at the Montgomery County Court House. The IRS, which never gets tired of looking at Nesline's tax returns, can't even talk to the bride now . . .

Just before she took off to Geneva to make a speech last week, Commerce Secretary Juanita Kreps was asked whether she owes her new look to a plastic surgeon. She replied: "Let's just say that, like President Carter, I've decided to part my hair on the other side" . . . It is no criticism of Bobby Short's considerable talent, but guests got restive at the musicale Fairfax Hotel owner John Coleman gave recently. "Washington's idea of a big musical evening," Coleman was told afterward by a politically astute friend, "is sitting around listening to Rep. Tip O'Neill singing Irish ballads."

Coleman, whose friends call him "Gatsby," brought together an unusual group of people. Let it now be explained that Princess Lee Radziwill came because architect John Warnecke, friend of all the Kennedys, asked her. Lee recently moved her interior-design business out of her apartment (it got so "messy," she complained) and into Warnecke's suite of offices in Manhattan. She was thrilled when the building management put her name up on its lobby roster of tenants, even though they left off "Princess."