GLOBAL MARKETS-Shares down as markets brace for Nvidia results, oil prices rise after Chevron ban

By Chibuike Oguh and Samuel Indyk

NEW YORK, May 28 (Reuters) - Global shares were lower on Wednesday, poised to snap two straight sessions of gains, with markets bracing for Nvidia's NVDA.O results while oil prices rose amid supply concerns after U.S. authorities barred Chevron CVX.N from exporting Venezuelan crude.

Market sentiment had been lifted by easing of trade tensions between the U.S. and Europe, after President Donald Trump delayed plans to impose 50% tariffs on European goods. Trump said on Tuesday the European Union's move to set up trade meetings was positive.

Investor attention is now focused on Nvidia's earnings, which are due after markets close. The chipmaker is the last of the "Magnificent 7" tech companies to report earnings this season.

On Wall Street, all three indexes were trading lower led by utilities, energy, materials and real estate stocks. Nvidia's shares were flat.

The Dow Jones Industrial Average .DJI fell 0.15% to 42,279.69, the S&P 500 .SPX fell 0.16% to 5,911.92 and the Nasdaq Composite .IXIC fell 0.15% to 19,171.32.

Europe's STOXX 600 .STOXX was down 0.53%, having risen over the last two days on the back of Trump's EU tariff pause. Britain's FTSE .FTSE fell 0.47%. MSCI's gauge of stocks across the globe .MIWD00000PUS fell 0.24% to 879.01.

"There is renewed confidence that Nvidia can beat the consensus estimates," said Chris Weston, head of research at Pepperstone.

If Nvidia comes through with better-than-expected sales and profit margins, "the rally is on," Weston added.

The Trump administration issued a new authorisation for Chevron CVX.N that would let it keep assets in Venezuela but not export oil or expand activities, Reuters reported on Tuesday, citing sources.

Brent crude futures LCOc1 rose 1.11%, to $64.80 a barrel, while U.S. West Texas Intermediate crude CLc1 gained 1.36% to stand at $61.72 a barrel.

U.S. Treasury yields were higher on the session, with the yield on benchmark U.S. 10-year notes US10YT=RR up 4.9 basis points to 4.483% and the 30-year bond US30YT=RR yield gaining 5.2 basis points to 4.9924%. Lacklustre demand for long-term Japanese bonds had weighed on trading overnight.

The U.S. dollar gained against peers including the euro and yen amid optimism about possible trade deals and following the soft demand for Japanese 40-year bonds.

The dollar strengthened 0.21% to 144.62 against the Japanese yen JPY=EBS, but it weakened 0.25% to 0.825 against the Swiss franc CHF=EBS. The euro EUR= down 0.1% at $1.1315.

Gold prices rose as traders sought bargains following the previous session's declines. Spot gold XAU= fell 0.1% to $3,297.10 an ounce.