In March, 2018, new rail pass, “Greater Tokyo Pass” was launched in overseas tourist market. This new deal covers all subway lines in Tokyo and major non JR railway services in Tokyo and surrounding area. Both Haneda and Narita airports are covered by this pass. You can start using this pass right after you arrive in Japan.
Nikko is one of the popular destinations from Tokyo. You can visit there as day trip. Of course if you stay there, you can visit many places in outside of Nikko city and also can enjoy hot springs in Kinugawa Onsen too.
I have written about access to Nikko by JR Pass before. At that time, I did not expect travellers who want to use other than JR Pass. But since I opened this website, I found many of you are looking for other ways or deals other than JR Pass