The incumbent NPF is contesting on 58 of the 60 Assembly segments in the state.
The Congress had nominated 23 contenders for the February 27 polls. However, the actual number of its candidates in fray is 18 after five of its contenders withdrew nominations.
The Nagaland Democratic Progressive Party (NDPP) and the BJP are contesting the election in alliance.
The Congress could not enter into a pre-poll tie-up with the NPF. But unofficial talks are now on with the NPF for a post-poll alliance to keep the BJP-NDPP out of power, a Congress leader said on condition of anonymity.
The leader said the Congress will reach out to the National People's Party (NPP) as well for the alliance "if need be" after the poll result is out on March 3.
The Congress does not have any member in the outgoing state Assembly. More than two years ago, all its eight legislators had joined the ruling NPF.
But we are going to attain double digit figure now. We will be a decisive force in the state as people here want a secular government and there is a strong undercurrent against the BJP, he claimed.
The Congress is seeking to return to the power after a hiatus of 15 years. The NPF and BJP shared power in the state since 2003, but severed ties ahead of the upcoming polls.
The result of the election, along with that of Tripura and Meghalaya, will be declared on March 3.