Colwyn Bay sealed an Evo-Stik Premier Division play-off place for the third successive season after a 1-0 victory at Hucknall on Saturday.
Jon Newby scored the only goal as the Seagulls beat Hucknall and the third-placed Welshman host Nantwich on Monday in their final game of the season.
FC United of Manchester and Bradford Park Avenue have already joined Colwyn Bay in the play-offs.
North Ferriby United and Buxton are battling for the final play-off spot.
FC Halifax Town have already sealed automatic promotion to the Blue Square Bet North Division as champions.