Chair once used as an instrument of punishment — Old Nick got us (anag) (7,5)
I believe the answer is:
ducking stool
(Other definitions for ducking stool that I've seen before include "Offenders took a dip in it" , "Chair once used to punish offenders" , "Chair for submerging offenders" , "Old form of punishment using water" , "Old instrument of punishment, using a chair and water" .)