Officials with Iran’s Foreign Ministry are giving indications that the Vienna negotiations are not just "stalled" but effectively over. They say they are prepared to return to Vienna to sign the final deal, but not if it’s just for more negotiations.
Its not always clear how the Vienna talks are going since the US and Iran have been the only really negotiating parties for weeks, and they don’t meet face to face. Indirect talks through EU negotiators look similar no matter how active they are.
All the reports of things being "close" seem to be accurate, with Iran interpreting things as finished, and just waiting for the US to settle any internal issues on accepting the final pact.
The big question remains the removal of Iran’s Revolutionary Guards from the US terror blacklist, something that is politically difficult for the US. Iran is also keen to get a US assurance that the next president won’t unilaterally withdraw from the deal, but that may not be achievable.
Iran’s Foreign Ministry spokesman Saeed Khatibzadeh accused the United States during a Monday press conference:
Khatibzadeh accused the United States of bringing the talks to a "suspension point." He said, “What has become clear for us in the last two weeks is that [US President Joe] Biden and the White House have not made a decision.” He continued that the United States has made the nuclear talks a "hostage" in domestic partisan issues.
...He added, “The US is responsible for the suspension of the negotiations.” If talks are resumed, the United States must provide a “logical answer” to Iran’s demands, Khatibzadeh said.
State Dept officials offered an unusually upbeat assessment, saying they believe differences can still be overcome. This is a stark difference to their usual predictions that the deal will fall apart. It’s not clear if they picture more negotiations either, or if they, who also believe the deal is near, might resolve the last little bit on their own.
Iran’s Foreign Ministry also indicated openness to resume other talks in the region to resolve key issues outside of the nuclear deal, including getting back to bilateral talks with Saudi Arabia.
Efforts to keep regional issues separate from the nuclear one is probably a good idea, because some regional powers, like Israel and Saudi Arabia, are so generally hostile to Iran that they’re liable to use anything and everything as an excuse to pressure the US away from a nuclear pact.