The decision was taken at a meeting of the BJP legislature party at the state BJP headquarters in the presence of three central observers, who had discussions with the 54 newly-elected legislators.
Union ministers Sarbananda Sonowal and Arjun Munda and senior party functionary Dushyant Gautam are observers for Chhattisgarh.
The official announcement is expected soon.
59-year-old Sai, a tribal leader who won the assembly election from the Kunkuri (ST) seat in North Chhattisgarh, had earlier served twice as the state BJP president and later as Union minister of state for steel.
The tribal leader was a Union minister from 2014 to 2019 in the Modi Cabinet. However, he did not get a party ticket to contest the 2019 Lok Sabha polls when the BJP leadership replaced all its sitting MPs with new faces after its defeat in the assembly polls in which BJP could win only 15 out of 90 seats in the Vidhan Sabha.
Born on February 21, 1964 at a village in tribal Jashpur district, Sai was a member of assembly of undivided Madhya Pradesh for two terms from 1990 to 1998 and was elected to the lok sabha in 1999, 2004, 2009 and 2014.
Watch BJP names former Union minister and tribal leader Vishnu Deo Sai as next Chhattisgarh CM