Nishio is a city located in Aichi Prefecture, in the Chūbu region of Japan. As of 1 October 2019, the city had an estimated population of 169,984 in 65,553 households, with a population density of 1,054 persons per km2. The total area of the city was 160.22 square kilometres. It is a regional commercial and manufacturing center and the country's leading producer of powdered green tea.