If you dream you are nagging at someone, you need to think about the truth or false allegation in this dream. If you are nagging, then you might like to change this. You may consider using a different approach to resolve the issue.
If you dream you are being nagged at, then look at the identity of the person berating you. Do you see this nagging in real life? If not, then this dream warns you of this threat. The nagger is your antagonist and you need to be careful of them.