"To all Arab peoples in the gulf countries of Saudi Arabia, Kuwait, Qatar, Bahrain, UAE [United Arab Emirates] and Oman: What is the alternative to an understanding between Iran and world leaders? It is regional war," The Daily Star quoted Nasrallah as saying in a rare public appearance at a Beirut gathering late Wednesday.
Israel is working to prevent a deal between the West and Iran.
"Israel knows well that it can start such a war but it will fail to keep it confined to a specific area," he warned.
Talks between Iran and the P5-plus-1 countries (Britain, Russia, China, France, the United States and Germany) infuriated Israeli Prime Minister Binyamin Netanyahu, Nasrallah said.
"Unfortunately, some Arab countries support Israel in its fatal choices, so just as they reject a political solution in Syria, they oppose a deal with Iran," he said.
Saudi Arabia is misguided if it thinks the outcome of talks between Iran and the West will lead to a compromise with Hezbollah, Nasrallah said.
"Do they really think that Iran, during the international negotiations, would abandon the resistance and hand over the country to the other side? This is in your dreams only and will never happen," he said.
"If the situation heads toward regional war, then everyone should worry and the others should be even more worried. But if there is understanding, our side will emerge stronger locally and regionally," Nasrallah said.