I actually kinda like this show. I used to watch it when I was little and I still watch it.
Also, I don't think Nina Needs To Go is inappropriate. Why? This is why:
There are disgusting stuff in people's bodies, which are pee, poop, burps, farts, and weird smells. Many people find them disgusting, embarrassing, or rude, so they rarely talk about them. That is actually a shame. People should talk about these things more often, because they are vital to a healthy life and are full of fascinating science.
So this is why I think this show is not inappropriate.
If Nina really needs to pee, it is not so bad to watch this show.