Sculptor Louise Nevelson, eyes flashing, feels strongly about President Reagan's plan to honor Nazi dead. But by last night she had changed her mind about protesting today at a White House luncheon for the first 12 recipients of the National Medal of Arts.

"I was prepared. But Elie Wiesel said it all. I couldn't top that," she said last night at a party honoring the medalists.

Wiesel, who received the Congressional Gold Medal on Friday in an Oval Office ceremony, criticized Reagan's plan to lay a wreath at Bitburg cemetery, where SS members are buried.

In explaining her feelings, Nevelson said, "There's a time and a place. You go to a funeral, you cry. You go to a wedding, you rejoice. The event tomorrow is a celebration. I wouldn't want to break that mood. Tomorrow is not the place to bring up such matters. The Oval Office is the place."

Even so, the 85-year-old sculptor said, "I feel so strongly about it. I hope we're going to win on this matter. But if something isn't done to correct it, I won't hesitate to make a statement."

Last night, Ambassador at Large for Cultural Affairs Daniel Terra entertained eight of the honorees at the State Department's new Benjamin Franklin ballroom. In addition to Nevelson, those honored were actor and director Jose Vicente Ferrer, opera singer Leontyne Price, author Ralph Waldo Ellison, composer Elliott Carter, National Gallery of Art board chairman Paul Mellon and Lincoln Center patron Alice Tully. Hallmark Cards Inc., the corporate medalist for its "Hallmark Hall of Fame" television series, was represented by Christopher Clouser, a company vice president.

New York City Ballet founder Lincoln Kirstein and choreographer Martha Graham did not attend the party last night but are expected at the ceremony today. Also missing were artist Georgia O'Keeffe, who was represented by National Gallery director J. Carter Brown, and Los Angeles Music Center patron Dorothy Buffum Chandler, represented by her daughter Camilla Chandler Frost.

Some quick portraits of the artists as award winners: Ferrer, at 73, looking as young as he did when he fought and recited his way through "Cyrano de Bergerac," said he is currently talking to NBC, "which is very hot on a program called "The Covenant" about an evil patriarch.

"The arts in America aren't as important an element in the national life as those who practice them wish they were," Ferrer said. "I'm just an interpreter, but the truly creative people, the writers, the composers, make a great contribution in helping people to find release from their anxieties." Ellison, author of the landmark book "The Invisible Man," admitted that he has "a great big manuscript that's driving me crazy. I never expected my first book to attract much interest. When that happens you feel you have to do the best you can on the next." His wife, Fanny Ellison, said, "He writes all the time. He has several things going." Mellon, who doesn't like the spotlight, escaped from the receiving line and had to be hunted down in the great hall to be brought back to have his picture taken with the rest of the medalists. He said that "anything that helps the arts makes me happy. There's never enough money for the arts, despite everything individuals and governments do." Price introduced her brother, retired Army general George Price, who became her manager in January. "I've been in charge of killing all these years and left the singing to my sister. But now she's asked me to be her friend, company, manager, brother and travel with her. I'm glad to do it. It's bringing the family together," he said. Alice Tully, who gave a hall to Lincoln Center, echoed Mellon by saying, "You can never do enough for the arts. At least the government does more now than they did. I'm grateful for what they do. And I hope they won't cut back more." Nevelson, as usual assembled as if she were one of her own great sculptures, said she plans to give many of her works and her papers -- and a case full of jewelry -- to the Berliawsky (her maiden name) Nevelson wing of the Farnsworth Museum in Rockland, Maine, her home town. Her companion and biographer, Diana MacKown, wearing a Nevelson sculpture as a necklace, said, "She'll have total control of the wing -- architect and everything."