Yes, you can have your mod on the Nexus (or wherever) for free, and also have it in the Workshop with a price attached.
However, for this experiment to work you'd have to upload it to Steam under an entirely separate identity, a new Steam account, so that it looked as if it were being stolen from you. You might also have to post a takedown complaint as yourself.
That, right there, would almost certainly count as deliberate deception of Valve on your part (or be interpreted by them as such), and would almost certainly be a violation of Steam's terms and conditions. I'd truly hope the consequences couldn't extend as far as a total lockdown of your Steam account (both/all of them), but you might want to think very carefully about the worst-case consequences before proceeding.
And do some very careful reading of all the relevant terms-and-conditions for Skyrim, CK, Steam and Steam Workshop.
[edit]
If I misunderstood what you meant by 'protected by the workshop "moderators"', I apologise for the waste of screenspace