While NBC' SALT II debate televised live last night from Kennedy Center may have ended in a draw there was no question that the party afterwards in the North Atrium foyer was a success.

NBC executives and the principals of the debate were busily celebrating "A pretty good idea" that they had pulled off.

Over shrimp and chicken crepes Adm. Paul Nitze was questioning how he had come across on television, and commenting on the fact that proper debate procedure had been very carefully followed.

"Everyone was remarkably disciplined," he observed ". . even the civilians."

Moderator John Chancellor was praised for his masterful performance in keeping the debaters on time, especially during the last five minutes when Adm. Isaac Kidd's question from the floor threatened to fill the remaining time. "I may have been the first human being ever to interrupt him," said Chancellor. "I don't even think his parents ever interrupted him."

Joseph Angotti, executive producer of the program, and Gordon Manning, vice president of NBC News. were emgaged on a mutual admiration debate of their own. each crediting the other for the success of the show. That one, too, ended in a draw, when retired "Meet the Press" impresario Lawrence Spivak joined the group and was given the ultimate opening credit for the idea of the debate. Said Manning, "I want to give Larry Spivak credit. I had the idea for this debate and went to see hem when I learned how successful "the big issue' was in the '50s. He refined the idea in my mind."

Averell Harriman was also reviewing the evining and was somewhat concerned about his question from the floor. "I didn't think (it) was too rude, did you?" Not many did.

Adm. Noel Gayler was not so much concerned about how he come across as he was about the issue had been presented. "I spent a couple of hours last night rereading John Hersey's 'Hiroshima' just to get the feel of this . . . to think, that was what we'd call a small tactical weapon now." "Yes," responded Lester Crystal, president of NBC News and host of the evening's reception, "this is one of two or three important issues we should get out there for debate."

"Sure, if we can get them off the gas lines long enought," replied Gayler, who was still worrying about the impact of the debate.

NBC executives, howver, were looking ahead to other possible debates, and those included that gas line. Manning said of the debate, "I wouldn't want them al to originate from Washington. I think we should take them around the country -- if we want to talk about gas problems we could go to Detroit, or we might go to Harrisburg if the debate was about nuclear safety. I would like to have a road show." He hastened to point out, however, that he had no authority and nothing was settled yet.

Chancellor, when questioned about furture debates, said he wasn't sure. But he was pleased with the way the evening had turned out. "I think this program was for the people who live in little towns and have lousy newspapers. They have to rely on the national news magazines and television for this kind of information. This was not for Washington sophisticates who KNOW A LOT ABOUT SALT."

He indicated some concern about a rating system that might not persuade the network to continue such debates:

"But just think," he said, "6 or 8 or 10 million concerned Americans may have learned a little more about this issue tonight. SALT II is very difficult to undertand. Right now I am suffering from a data overload myself. I have been working on it since 1969. Most Americans would need to take a six-month course in it to understand. Something like this helps. The only way to approach it is to nibble away at it." CAPTION: Picture, Adm. Noel Gayler