you need to use vocative.
Nic nie wiesz, Janie Śniegu/ Nic nie wiesz Jonie Snow
The precedent sentence was "Nic o was nie wiem". Does the word order make a difference?
Well, the stress is mostly at the end of the sentence, unless you put it somewhere else by intonation. "Nic o was nie wiem" sounds more natural to me than this one.
[Nic] [o was] [nie wiem] - mix these groups and get corect polish sentence every time :)
I said "Do you not know anything about us?" and got it wrong. It was a one word difference!
The Polish sentence is a statement, not a question, so it needs to be translated to a statement.
How can you differentiate between 'There is nothing you don't know about us' which is the same (Nic nie wiesz o nas) or this 'you do not know anything about us'?
I would propose: There is nothing you don't know about us - Nie ma niczego, czego byś o nas nie wiedział(a). (singular you)
How about shortening to, you know nothing about us, or is it already accepted?