hello sabrina, in fact it depends on what you're talking about and how you use it, i mean "il n'y a rien à voir" that means that there's nothing which is worth seeing. Or you can say "cela n'a rien à voir" this not the same meaning, usually you say that to another person when you totally disagree with him or her or if you want to say to the other person that she or he's misunderstanding what you're telling them. I hope that i could help you.

nothing to see

It could be translated as "there's nothing to see". It means that there's nothing interesting. You can use it to refuse something you aren't interested in, for example.