Nicholas Duchnowski (; 12 December 1733 â 25 June 1805) was a bishop of the Ruthenian Uniate Church, Bishop of Supraà Âl and all unites in New East Prussia.
After the death of Theodosius Wislocki, Nicholas Duchnowski was selected as the locum tenens bishop of Supraà Âl until he was consecrated in 1804.