The White House previewed four ambassadorial nominations yesterday, including plans to nominate John H. Kelly, a career foreign service officer, as Reginald Bartholomew's successor in the hot seat in Lebanon. Kelly, who will turn 47 on Monday, has held diplomatic posts in Turkey, Thailand and France, and several jobs of deputy assistant secretary rank in Washington.

One of yesterday's announcements -- of Reagan's intent to appoint Julian M. Niemczyk, a veteran intelligence officer and former official of the Republican National Committee, ambassador to Czechoslovakia -- was made over what sources describe as the prostrate forms of career foreign service officers. The FSOs were lobbying for the appointment of Sol Polansky, one of their own, who has extensive experience in the Eastern bloc.

Other nominees announced were Princeton Nathan Lyman, a career officer who has been deputy assistant secretary for African affairs since 1981, to be ambassador to Nigeria; and Carol Boyd Hallett, 48, to be ambassador to the Bahamas. Once a California assemblywoman whose constituents included citizens Ronald and Nancy Reagan, Hallett is now national field director for Citizens for America, a private group that lobbies for Reagan administration programs. A Chile Effect . . . A few end notes from Sen. Jesse Helms' (R-N.C.) recent trip to Chile, where his outspoken observations about democracy in action prompted protests from the State Department.

"The editorials aren't treating us very nice," observes Helms aide Deborah DeMoss about American press reaction to his statements from Chile. He has been roundly roasted for saying that democracy in Chile is proceeding at a fine clip; that the U.S. should recall its ambassador for attending the funeral last week of a 19-year-old American whom witnesses say was burned to death by Chilean soldiers; that the State Department has led the president astray and distorted his policies; and that "The press in my country shames me" for its "habit of being very unjust with anticommunist governments" such as that of Chilean strongman Augusto Pinochet.

DeMoss recently elaborated on that last comment, telling a reporter that the reason for the harsh press comments on Helms's trip is that, "It's generally because no one has information on what's going on there right now. People are uninformed on current events in Chile. All they have are the major news media."

DeMoss, who advises Helms on Latin American affairs, also said that the senator, his wife and three aides traveled to Chile as guests of the Chilean National Agricultural Society. The society is a conservative bulwark of the Pinochet regime founded a century ago by the country's large landowners. As chairman of both the Agriculture Committee and the Foreign Relations Subcommittee on the Western Hemisphere, Helms is a pretty good catch in the paid guest category. Striptease . . .

The Interior Department's new associate solicitor for surface mining is Alan Sears, who, until recently, was the executive director of the attorney general's Commission on Pornography. In addition to the predictable jokes about taking the strip out of strip mining, in-house wags are wondering what Sears will have to say about the department's recreation association bookstore, which sells, among other items of interest to Interior employes, copies of Hustler and Penthouse. Airborne . . . After waiting long enough to prompt the rumor mill into high gear, the Reagan administration has renominated Jim Burnett as head of the National Transportation Safety Board. Because the seat has been empty since Burnett's term expired in May, scuttlebutt -- and congressional admirers of Burnett's record -- have it that the administration was tempted not to reappoint Burnett, and to turn instead to someone who might be less avid in criticizing the administration and the FAA. Burnett's confirmation is considered a sure thing.