He earned his Doctor of Literature degree from the University of Tokyo (UTokyo) in 1962.

He is widely believed to have conceived the name of the current era of the official calendar of Japan, Reiwa (令和, 2019-).

[4] Nakanishi studied at the Department of Japanese Literature at the University of Tokyo (UTokyo), where he was supervised by the Japanese literary scholar Senichi Hisamatsu (久松潜一).

His master's thesis was titled 'A Study on the Prosaic Nature in Early Japanese Literature (上代文藝における散文性の研究)'.

[3] In 1970 he was awarded the Japan Academy Prize for his research in comparative literature and the Man'yōshū,[3][10] and in 2013 he received the Order of Culture.