Nishii was born in Tokyo in 1946. He graduated in economics from Keio University in 1968, and shortly after this moved to the company publishing Mainichi Shimbun, rising via stints at Sunday Mainichi and Mainich Graph to become editor in chief of Camera Mainichi from 1983 until the magazine folded in 1985.

After the demise of Camera Mainichi Nishii worked as an editor for various book-publishing projects of Mainichi Shinbun-sha.

Nishii first proposed the Society of Photography Award and played a major role in setting it up.