Nancy Reagan received the first annual Woman of the Year award from the United Service Organization of Metropolitan Washington yesterday in an emotional presentation by ABC's Barbara Walters before a luncheon crowd of 1,200, some of whom as corporate sponsors had paid $5,000 a table.

"What it does is nourish the heart and feed the soul," Walters said of the USO. "What makes Nancy Reagan special to me is she also nourishes the heart and feeds the soul."

Mrs. Reagan called the USO "the equivalent of a big warm hug for our men and women in uniform" when she accepted the award. "I'm especially honored to get it from the USO and get a little hug myself."

Joking that the award might make her difficult to live with from now on, she told a story about her first fan letter when she was a young actress at Metro-Goldwyn-Mayer.

"I was not exactly what you would call a seasoned professional, jaded by public acclaim. I was so excited . . . that I pinned it on my dress and wore it around the studio for weeks until they said you really have got to take that thing off. I'd like to do it now," she said, looking at the small modern metal sculpture by Robert M. Engman, "but I don't quite see how."

Mrs. Reagan described an interview she had with Walters, the first she gave after the assassination attempt on the president.

"I'm sure I could never do it again, it was still too fresh, too raw, but Barbara was very sensitive. Suddenly, I just started to open up and I think we shared a few moments that were not seen on the camera, although maybe some were. It was something between the two of us," Mrs. Reagan said, "and I'll be ever grateful for her understanding that day."

Walters, who shared the head table with, among others, Defense Secretary Caspar W. Weinberger, also talked about that interview and how Mrs. Reagan confided that she sometimes ate bananas in the middle of the night because she was so worried about her husband's safety.

" 'I really prefer apples but I don't want the crunch, crunch to wake the president' ," Walters said the first lady told her.

Describing both Reagans as committed to volunteerism, Walters said "a political wife must participate in the problems and concerns of the people her husband governs. Mrs. Reagan's interests were chosen not out of show but for love. She waited and took her time amid some criticism before she decided where her talent and her experience could best be used."

Walters cited Mrs. Reagan's work in the Foster Grandparents program and in calling national attention to drug-abuse rehabilitation programs around the country.

"I think Mrs. Reagan is often misunderstood by a public that's ready to swallow gossip, and sometimes by the press . . . because we are ever hungry, we look for stories," Walters said.

Corporate sponsors included a table of Nancy Reagan's California pals, among them Betty Wilson and Leonore Annenberg. At a Texas table with Lilla Tower and Susan Baker was industrialist H. Ross Perot. Elsewhere in the huge yellow and white tent were wives of Cabinet officers, diplomats, senators and congressmen.

An estimated $200,000 was expected to be raised through the sale of tickets that ranged from $50 to $500 and $5,000. Guests ate at round tables covered with camouflage netting where centerpieces of army canteens were filled with flowers. The three-course meal, which included smoked salmon and kiwi fruit tart, was served on tin mess plates.

"Exactly the way they served smoked salmon in the field," quipped retired Air Force major general John Alison, now a vice president with Northrop aviation.