There's a whole heap of resources on VB.NET from the Wiki:
https://github.com/NancyFx/Nancy/wiki/Blog-Posts%2C-Video-%26-Audio#vbnet
To answer your question though.
The most basic example would be something like this:
Imports Nancy
Public Class HelloModule
Inherits NancyModule
Public Sub New()
MyBase.Get("/") = Function(parameters) "Hello World"
End Sub
End Class
Just to return a string.
If that's working then it probably something to do with your view, or the parameter to the view.