In 1590, when Ieyasu TOKUGAWA was transferred to the Kanto region, Nagamori was allowed to rule the Shimosa-Yamazaki Domain with an estimated rice yield of 12,000 koku as a reward for his distinguished services as a warrior.
天正18年（1590年）、徳川家康が関東に移封されたとき、それまでの戦功を賞されて下総山崎藩1万2000石を与えられた。