The agreement, struck over the weekend, will see some sanctions that were imposed on Iran over its nuclear program eased in exchange for Tehran halting some of its most sensitive atomic work.
"What was achieved through this agreement is a major victory for Iran and to all the people of the region and it is a defeat for the enemies of these people," Hezbollah said in a statement.
"(It is) a model victory and world class achievement which the Islamic state adds to its record which shines with victories and achievements."
Israel, which has fought Hezbollah, denounced the nuclear deal as a "historic mistake".
The Shi'ite Muslim Hezbollah, founded with Iranian help in the 1980s, has grown into a powerful political and military force and is fighting alongside President Bashar Assad's army in Syria's civil war.
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