I want to develop the Nintendo Switch, what do I need to do with Nintendo’s developer?
You need to create an account with Nintendo’s Developer Portal. Once you’ve done that you need to contact them through it to request permission. After you’ve been approved you will have to purchase a devkit from them, download their copies of Unity, etc. Any information beyond that is behind an NDA and has to be asked on the portal.
I have not received a response from them, have I not been accepted?
They probably get a stack of applications every day. It could take them a while to get back to you.