Charles Stevenson ceded his powers to Lieutenant Governor Frank Bell on September 1, 1890 due to disability. Stevenson died three weeks later on September 21, 1890. Bell thus served the remainder of the term.
The primary source is the original manuscript canvass, located at the Nevada State Archives in Carson City. The results were also printed in the 1885-1886 Biennial Report of the Secretary of State.
Source for Popular Vote data: Nevada State Archives, "Governor," Canvass of Votes Cast at the General Election held in the State of Nevada on the 2d day of November, A.D. 1886 (Carson City, 1886)