Political insurgents tend to overlook things like scheduling conflicts with another country's revolution, so what a mess, China and Nigeria both wound up celebrating Oct. 1 as Independence Day.

This is actually no problem in China and Nigeria, which are 5,000 miles apart as the Peking duck flies. But in Washington, the Nigerian Embassy has to have an anniversary lunch and the Chinese Embassy, a dinner.

"Ah, my twin!" said the Nigerian ambassador to the Chinese ambassador at the Nigerian Embassy yesterday. They look nothing like each other.

At 20, Nigeria is 11 years younger than the People's Republic of China, and yesterday, in between shaking hands in his blue-flowered native costume called an agbada, Nigerian Ambassador Olujimi Jolaoso sized up the first two decades of this young nation,the richest and most populous in Africa.

"We are a developing country by all definitions," he said. "It's just that we are fortunate to have some of the resources that we need for such development. We are a little bit luckier than most of the African nations."

Some might say a lot luckier, considering that Nigeria makes an annual $15 billion in oil revenues, is the second-largest oil supplier to the United States and enjoys a $6 billion trade surplus with Washington. Next week, the new Nigerian president, Shehu Shagari, is scheduled to meet with Jimmy Carter at the White House for a session that, predicted the ambassador, will be almost wholly economic.

The anniversary lunch itself took place around the backyard pool of the embassy in Chevy Chase, a pool that despite the warm fall weather went completely ignored. Oh, people noticed it well enough, but nobody felt the urge to leap in.

"I served 10 years in Africa and I never went to a party where they didn't end up in the pool, evening dresses and everything," said Wilbert Luck, late of the State Department but now of HUD.

The thing was, this was Washington. Briefcases. Tab. Pantyhose. And "I'd like to stay but I have a meeting with Ms. Muckety-Muck . . ."

To be honest, nobody said Ms. Muckety-Muck. But here's a selection of what they did say on the backyard deck, which was full of ambassadors, Howard University people, oil executives, World Bank folk and cracks a lady in high heels tripped on:

"I say we take their money, give them a little psychological boost, and then just fold this into it."

"We're really at the point where we're going to take the whole damn thing and move it to another city, for God's sake."

"The report has been released and there was no money missing."

Wedged onto the deck was the Chinese ambassador, Chai Zemin. Somebody asked him about the possibility of Soviet involvement in the war between Iran and Iraq.

"It's hard to tell at this stage," he replied through his interpreter. "The Soviet Union is biding its time. We believe we should not give them any opportunities which they could exploit, so we think it's important to implement the Security Council resolution to urge the conflicting parties to stop fighting."

Then off he went, presumably to get ready for dinner.