Private onsen in Nyuto Onsen

Is there a mixed onsen in Nyuto Onsen?

Yes: Ganiba Onsen, Tsurunoyu Onsen, Taenoyu, Magoroku Onsen, Kuroyu Onsen. If what you want is to bathe together as a couple or a family, a private onsen is usually how it is done in Japan: the 3 below have a bath your group uses alone. Where Japan’s mixed baths are, and what to wear