* Nike top Dow pct decliner after rating cut
* Oil prices fall nearly 2 pct
* S&P 500 remains below 50-day moving avg
* Dow up 0.03 pct, S&P flat, Nasdaq down 0.2 pct (Updates to late afternoon)
Aug 21 (Reuters) - U.S. stocks were little changed on Monday as simmering tensions between the United States and North Korea kept investors on edge, while a drop in oil prices weighed on energy shares.
Investors also are awaiting this week's meeting at Jackson Hole, Wyoming, between Federal Reserve Chair Janet Yellen and global central bankers. Investors are angling for the slightest hint on where monetary policy is headed.
"That confluence of strong growth and low inflation, which is somewhat like nirvana for equity investors, we don't think can last forever," said Wayne Wicker, chief investment officer at ICMA-RC in Washington, D.C.
"We're hopefully getting a couple of more data points to see where the Fed takes their temperature on where they're feeling the economy is at this juncture so that we can anticipate if something happens in the fourth quarter or not."
The United States and South Korea began long-planned joint military exercises on Monday, heightening tensions with North Korea which called the drills a "reckless" step toward nuclear conflict.
Part of the recent decline was due to escalating tensions between the United States and North Korea.
The S&P 500 energy index was down 0.8 percent, leading sector declines in the S&P 500, after crude oil prices fell nearly 2 percent, pulling back from last week's rally.
The Dow Jones Industrial Average was up 5.66 points, or 0.03 percent, to 21,680.17, the S&P 500 had lost 0.01 points to 2,425.54 and the Nasdaq Composite had dropped 12.67 points, or 0.20 percent, to 6,203.86.
While the benchmark S&P 500 index is still up 13.6 percent since the election, it had fallen 2.1 percent in the last two weeks. That's the most since the two weeks before the election.
Last week, U.S. President Donald Trump fired chief strategist Steve Bannon and disbanded some business councils, raising concerns about the Trump administration's ability to implement its pro-growth agenda of tax cuts and infrastructure spending.
The Dow briefly fell below its 50-day moving average, while the S&P 500 remained below the 50-day technical level.
Nike shares fell 2.8 percent after Jefferies cut its rating and price target on the stock.
Johnson Controls rose 3.2 percent to $38.22, among the top S&P gainers, after saying its CEO change would happen earlier than announced.
Herbalife was up 9.8 percent after the nutritional supplement maker said it would buy back $600 million of shares after ending talks to be taken private.
Declining issues outnumbered advancing ones on the NYSE by a 1.07-to-1 ratio; on Nasdaq, a 1.53-to-1 ratio favored decliners. (Additional reporting by Sruthi Shankar in Bengaluru; Editing by Nick Zieminski)