Lifespan: Unknown to 2/11 of Tenshō 11 (1583)
Other Names: Jirō
Name Changes: Morita Suketane → Nasu Suketane
Rank: sengoku daimyō
Title: Master of the Office of Palace Repairs
Father: Nasu Masasuke
Mother: Daughter of Ōtawara Sukekiyo
Siblings: Takasuke, Suketane, Sukekuni
Wife: [Formal] Daughter of Ashino Suketoyo)
Children: Sukeharu, Makino Akitaka, Shōtōin (formal wife of Satake Yoshinobu)
Nasu Suketane served as a sengoku daimyō of Shimotsuke Province. He was the twentieth head of the Nasu clan.
Suketane was born as the second son of Nasu Masasuke, the eighteenth head of the Nasu clan. Suketane inherited the Morita clan but came into conflict with his older brother of a different mother, Nasu Takasuke (the nineteenth head of the Nasu clan) and absconded for a period of time. In 1551, after Takasuke was lured by Haga Takasada and murdered by Senbon Suketoshi, Suketane returned and became the next head of the Nasu clan.
Initially, he joined forces with the Satake clan of Hitachi Province and battled against the Yūki and Ashina clans but, in 1555, he collaborated with Hōjō Ujiyasu and Ashikaga Yoshiuji. In 1560, when Satake Yoshiaki and Yūki Harutsuna clashed, Ashina Moriuji supported Harutsuna while Suketane backed Yoshiaki. On 3/26, at the Battle of Odakura in Mutsu Province, even Suketane incurred injuries in the course of the conflict. As a result, Suketane censured Ōzeki Takamasu and Ōtawara Tsunakiyo (siblings who were his retainers), assigning responsibility to them and triggering a confrontation with the Ōzeki and Ōtawara clans. Takamasu responded by taking members of the Upper Nasu family and abandoning Suketane and colluding with the Satake of Hitachi Province. On 5/15, Suketane encouraged Matsumoto Michikatsu, a retainer of Takamasu, to plot his assassination. When Takamasu learned via Satake Yoshiaki of the plot, he had Okino Yoshishige guard him. To expel Suketane, Takamasu made plans to back Satake Yoshihisa (later known as Nasu Suketsuna), the younger brother of Satake Yoshishige. Thereafter, from 1563 to 1567, Suketane engaged in repeated battles against Takamasu (who obtained reinforcements from Yoshishige). This included attacks below Karasuyama Castle, but Suketane repelled them. On 8/24 of Eiroku 9 (1566), Suketane routed Satake Yoshikata (a retainer of Yoshishige who supported Takamasu) at Kaminaga in Shimotsuke Province. In 1568, Takamasu and Tsunakiyo (siblings) settled on the condition that Suketane retire.
In 1570, Yoshishige toppled Ōyamada Castle in Shimotsuke but, in 1572, he settled with the Satake clan. At this time, he arranged for the engagement of his daughter to Satake Yoshinobu who was three years old. Further, he ceded the Mumo and Motegi areas to the Satake and permitted landholdings by the Satake in the territory of the Nasu clan.
In 1574, when conflict erupted between Shirakawa Yoshichika (later Komine Yoshichika) and Yoshishige in regard to Yoshichika’s base at Akadate Castle in Mutsu Province, Suketane joined Ashina Moriuji in support of Yoshichika. In 1578, Suketane entered into a covenant with the Satake in addition to the Utsunomiya, the Yūki, the Edo, and the Daijō at Ogawadai in Hitachi Province to oppose the Gohōjō clan. This culminated in the Battle of Ogawadai.
There is another theory that he died in 1586.