The opposition Zoram People's Movement (ZPM) in Mizoram on October 10 announced Shanti Jiban Chakma as its candidate in the Tuichawng seat.
The ZPM had in July announced its candidates for all seats in the 40-member Assembly, except Tuichawng.
Shanti Jiban Chakma, a former Chief Executive Member (CEM) of the Chakma Autonomous District Council (CADC), was earlier in the BJP.
The ruling Mizo National Front (MNF) has fielded Rasik Mohan Chakma, the incumbent CEM of the CADC, in the seat.
The Congress and BJP are yet to release its list of candidates for the November 7 elections.
The votes will be counted on December 3.