* European stocks rise, U.S. futures flat

* Traders mulling Iran peace talks and AI boom

* Nvidia ( NVDA ) stock slips despite earnings beating forecasts

(Updates throughout for morning European session)

By Harry Robertson and Gregor Stuart Hunter

LONDON/SINGAPORE, May 21 (Reuters) - European stocks

rose and U.S. futures flatlined on Thursday as investors mulled

tentative signs of progress in Iran peace talks, while Nvidia ( NVDA )

stock slipped despite the chip-making giant's earnings beating

expectations.

Europe's STOXX 600 index was up 0.2%, having fallen

earlier in the session.

Futures for the S&P 500 and tech-focused Nasdaq

were both little changed.

The S&P 500 rose 1.1% on Wednesday after three days

of declines as oil prices fell after U.S. President Donald Trump

said Iran talks were in the final stages, though he said he

could also restart attacks.

The rally carried over into Asia overnight, with MSCI's

broadest index of Asia-Pacific shares outside Japan

climbing 2.6%.

Samsung shares jumped 8.5% after the electronics

giant's union said it would suspend industrial action, averting

a strike that threatened global chip supply.

Investors in the U.S. and Europe on Thursday were left

mulling mixed messages from Trump on Iran. The U.S. president

said on Wednesday he could wait a few days for "the right

answers" from Tehran, but was also willing to resume strikes on

the country.

Pakistan was stepping up diplomatic efforts to keep

U.S.-Iran peace talks on track, as officials in Tehran said they

were reviewing Washington's latest responses.

"Conviction is lower this time," said Francesco Pesole,

currency strategist at ING. "Rhetoric from both sides remains

belligerent, and markets are more hesitant to chase optimistic

headlines after earlier disappointments."

NVIDIA UNDERWHELMS IN HOT AI MARKET

Shares in Nvidia ( NVDA ), the world's biggest company by

market capitalisation, slipped 0.4% in pre-market trading

despite the firm beating Wall Street expectations.

Nvidia ( NVDA ) on Wednesday forecast second-quarter earnings of $91

billion and announced an $80 billion share repurchase programme.

"Investors want the world from Nvidia ( NVDA )," said Dan Coatsworth,

head of markets at AJ Bell.

"Despite the company once again beating consensus quarterly

sales and earnings estimates, the shares fell in pre-market

trading on worries around the sustainability of its rapid

growth."

Questions about the durability of the AI rally have failed

to dent the massive rise in U.S. stocks, however, which are up

more than 8% this year.

In currencies, the index tracking the U.S. dollar,

which has been a safe haven for investors during the war, was

flat at 99.15.

It slipped from a six-week high of 99.47 on Wednesday on

hopes of progress in peace talks.

The euro was flat at $1.16 on Thursday, just above

a six-week low.

Meanwhile, 10-year U.S. Treasury yields, which

set the tone for borrowing costs around the world, were up 1

basis point at 4.58%.

They hit a 16-month high of 4.687% on Tuesday, as traders

continued to scrap their previous bets on Federal Reserve rate

cuts.