US envoy Steve Witkoff and Jared Kushner would take part in the negotiations, which were being mediated by Oman, a source briefed on the matter told Reuters, alongside Iranian Foreign Minister Abbas Araqchi.
US President Donald Trump said he would be involved "indirectly" in the Geneva talks and he believed Tehran wanted to make a deal.
"I don't think they want the consequences of not making a deal," Trump told reporters aboard Air Force One on Monday.
"We could have had a deal instead of sending the B-2s in to knock out their nuclear potential. And we had to send the B-2s."
Tehran knows that a previous attempt to revive talks was under way in June last year when Washington's ally Israel launched a bombing campaign against Iran, and was then joined by US B-2 bombers that struck nuclear targets.
Tehran has since said it has halted uranium enrichment activity.
A senior Iranian official told Reuters on Tuesday that US seriousness on lifting sanctions on Iran and avoiding unrealistic demands were key to ensuring effective talks in Geneva.
The official, who declined to be named, said Tehran was coming to the negotiating table with "genuine and constructive proposals".
The meeting took place on Tuesday at the residence of the Omani ambassador to the UN amid a heavy security presence.
The US military is preparing for the possibility of weeks of operations against Iran if Trump orders an attack, two US officials told Reuters.
Iran itself began a military drill on Monday in the Strait of Hormuz, a vital international waterway and oil export route from Gulf Arab states, which have been appealing for diplomacy to end the dispute.
Tehran and Washington renewed negotiations on February 6 on their decades-long dispute.
Washington and its close ally Israel believe Iran aspires to build a nuclear weapon that could threaten Israel's existence.
Iran says its nuclear program is purely peaceful, even though it has enriched uranium far beyond the purity needed for power generation, and close to what is required for a bomb.
Since the June strikes, Iran's Islamic rulers have been weakened by street protests, put down at a cost of thousands of lives, against a cost-of-living crisis driven in part by international sanctions that have strangled Iran's oil income.
Unlike last time, the US has now placed what Trump calls a massive naval armada in the region.
Washington has sought to expand the scope of talks to non-nuclear issues such as Iran's missile stockpile.
Tehran says it is willing only to discuss curbs on its nuclear program - in exchange for sanctions relief - and that it will not give up uranium enrichment completely or discuss its missile program.
On Monday, US Secretary of State Marco Rubio told a news conference in Budapest that it was hard to do a deal with Iran, but the US was willing to try.
Iran's Araqchi on Monday met Rafael Grossi, head of the IAEA in Geneva to discuss cooperation with the nuclear watchdog and technical aspects of the impending talks with the US.
On Tuesday afternoon, Witkoff and Kushner will take part in three-way talks with Russia and Ukraine as Washington attempts to coax Ukraine and Russia into an agreement to end Moscow's four-year-old invasion of Ukraine, the source said.
