The 27-year-old, who scored three times in 14 appearances for the Pilgrims during the second half of the 2016-2017 campaign, is staying put ahead of the new season.
Chapman's signing represents another key piece in Adam Murray's squad-building jigsaw and the United boss is delighted to keep last season's captain onboard.
"Chappy is a fantastic player at this level and coupled with the signing of Jamie McGuire, we now have two midfielders who have played numerous times together in promotion-chasing sides in League 2," reflected Murray.
"They both have fantastic experience too and that will rub off on the younger lads within the squad."