You will be told to play light armor and staff.
Do yourself a favor and try stuff for yourself, its half of the fun.

I'm a redguard and i'm doing fine. Screw min-maxing, go for the looks you want, you'll have to look at that toon for the rest of your gameplay time

What is the best class for nightblade?

A nightblade.

My NB alt has a very rogue like 5 medium/ 2 heavy dual wield build which is actually quite fun to play and is also putting out some satisfying dps although I haven't played any VR content with it yet so can't comment on that.

There seems to be a bit of a cookie cutter thing going on at the moment where apparently staff and light armour builds are the only way to go irrespective of what class you are. Personally I'd ignore all of that and just try whatever you want too because the other builds do also work and can be fun.