Nancy Kissinger, who enjoyed a brief run in the tabloids as "Bruiser" Nancy after allegedly throttling a woman who had insulted her husband Henry in Newark airport last March, was acquitted today of assault charges after a two-hour trial.

"A spontaneous, somewhat human reaction," Municipal Judge Julio Fuentes pronounced after the non-jury trial.

"I'm so glad it's over. Anything I say is going to sound idiotic. I'm just so grateful it's finished," Mrs. Kissinger said after hugs and kisses to her lawyers.

Mrs. Kissinger was charged last March with "simple assault," a misdemeanor, after a confrontation with Ellen Kaplan, a member of the Fusion Energy Foundation, a group associated with Lyndon H. LaRouche.

In that confrontation, according to testimony from a half-dozen witnesses, Kaplan and an associate, making hostile and combative comments, pursued the Kissingers at the airport. Kaplan at one point shouted to Kissinger, "Is it true that you sleep with young boys at the Carlyle Hotel?"

Subsequently, the "assault" transpired, though there were two views of the intensity of the experience on the part of the principals.

Kaplan testified that Mrs. Kissinger "grabbed me, had me by the throat, put her face close to mine, sneered, bared her teeth--she was wearing braces, and I kept thinking she's gonna bite me--and said, 'Do you want to get slugged?' "

On the stand, Nancy Kissinger did not deny that she had made the offer. But, she testified that she had been escorting her husband to Boston for a triple bypass heart operation and that he was under doctor's orders to avoid "upset of any kind." She said she had been merely trying to encourage Kaplan to clear out.

"I took her by the neck and pinched her," said Mrs. Kissinger, who stands about six feet tall to Kaplan's 5 feet 4 inches. "I did say to her, 'Do you want to get slugged,' but I just wanted her to stop and leave us alone in peace and quiet and stop all the upset."

Henry A. Kissinger, who was secretary of state in the Nixon and Ford administrations, took the stand and listed a number of insulting comments, beginning with Kaplan's shout of, "You're a little man, Henry." After the "assault," Kissinger testified, Kaplan made a remark along the lines that his wife was sleeping with the body guard, "Is he the one who's servicing you now, Nancy?" Kaplan also threatened the Kissingers. "I'll get you," she allegedly said.

Kaplan, on the stand, did not deny making belligerent statements. But she said, under cross-examination, it was her "right." She also said that after the confrontation, she was "very, very freaked out."

"I had never been attacked like that," she said.

In his closing statements, Judge Fuentes said that an assault had not taken place because, under state law, there must be bodily injury for an attack to be an assault.

After the verdict, Kaplan said that an "injustice" had been done and expressed the opinion that the Kissingers, who would leave Newark with a police escort, were treated like "the British royal family" in this country.

Nancy Kissinger just smiled. Asked whether she might do it again, she replied:

"I don't know. Lord knows."