The 26-year-old left-back has loads of experience at both league and non-league levels, having played for Sheff Wed, Northampton, Notts County and Scarborough.
The experienced defender has played 100 games in the Conference while at Scarborough and featured strongly in the Forest Green team last season including a return of six goals.
Derby-born Nicholson is manager Paul Buckle's seventh summer signing as the gulls prepare for the season ahead.
Source: http://www.confguide.com/newsArticle.do?id=6684