His Maldivian Democratic Party (MDP) rules requires a candidate to get approval from least 10 per cent of the party's 48,000 strong membership to win the nomination.
With 72 of the 258 ballot boxes still to be counted, Nasheed had recorded 26,609 votes in favour to 227 against.
Nasheed's MDP led a relentless pro-democracy campaign against the rule of Abdul Gayoom. The campaign culminated in the first ever multi-party elections in October 2008.
Nasheed, 45, became the first democratically elected president of the Maldives in 2008.
The events which led to his ouster in February this year are currently the subject of a probe.
The international community has called for early elections to end the political impasse after Nasheed claimed he was forced to resign as a result of a "coup".
The government of President Mohamed Waheed Hassan has said that elections would be constitutionally possible only after July 2013.