I think I watched most of the first season. Their friendship is really sweet and my yuri-trained brain saw their narrative going one direction. Turns out, heteronormativity is not only overtly prevalent, but also very nonsensical. Nana and Nana are literally straight for the sake of straightness. They have a lot of chemistry together. If their writer was just writing with a compelling story in mind, they would have ended up together. But they weren't, they were writing with straightness in mind and it shows. I gave up on the show and it rests as one of the most disappointing anime I have ever seen. Lovely pairing, though, and this picture is great.