The by-poll was necessitated following the resignation of Health Minister Lal Thanzara on August 18.
The younger brother of Chief Minister Lal Thanhawla resigned after reports about his alleged conflict of interest in government contracts with some business houses.
While NDA is yet to announce its candidate, the Mizoram People's Conference (MPC) has already decided to support the ruling Congress candidate and former health minister Lal Thanzara.