Toshinao was the son of Nanbu Nobunao and resided at Morioka castle. He supported Tokugawa Ieyasu during the Sekigahara Campaign, leading his men to aid Mogami Yoshiaki and Date Masamune against the forces of Uesugi Kagekatsu. After the campaign was concluded, Toshinao was confirmed in his 100,000 koku fief.
References
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005