Nicholson, who won three caps for Scotland from 2001 to 2004, waited until the end of his contract at Aberdeen before completing his move to the Coca-Cola Championship side.
Nicholson told www.pnefc.co.uk: "I´m glad to have my future decided. It´s been a bit of a weird summer for me, not knowing where I was going to be playing next season. To finally come down and get things sorted out has been brilliant."
Copyright (c) PA Sport 2008, All Rights Reserved.