He spent all of his playing career with the Nishitetsu Lions of Nippon Professional Baseball, and served as player-manager of the team from 1962 to 1969.

Nakanishi also managed the Nippon-Ham Fighters, Hanshin Tigers, Yakult Swallows, and Chiba Lotte Marines.

He had planned to attend Waseda University, but his parents negotiated Nakanishi's first contract with the Nishitetsu Lions without his consent.

He hit 12 home runs in his rookie season and subsequently decided to hone his power stroke.

However, both injuries sapped his effectiveness as a player and he succeeded Tokuji Kawasaki as Lions' manager in 1962, playing the field occasionally until 1969.