Career
His courtesy title was Tangō no Kami. Nishio Tadateru was the eldest son of Nishio Tadanaga, daimyō of Tsuchiura Domain, but was born in Suruga Province. In 1620, at the age of seven, he became head of the Nishio clan and daimyō of Tsuchura on his father"s death.
In 1621, he attended to Shogun Tokugawa Hidetada during his pilgrimage to the Nikko Toshogu, and were permitted to expand the size of his castle.
On February 11, 1649, his holdings were increased in size by an additional 5,000 koku when he was transferred to Tanaka Domain in Suruga. Tadateru was married to a daughter of Takenaka Shigeyoshi, daimyō of Funai Domain in Bungo Province.
His grave is at the temple of Myōgeneral-ji in present-day Ageo, Saitama.