He was released by Chesterfield at the end of the 2011–12 season, having made almost 300 league appearances for the club. In July 2012 he began training with Conference National side Grimsby Town, alongside former Macclesfield Town player Lewis Chalmers. After impressing in the club's 12–3 victory over Grimsby Borough he was offered a contract by the club, while Chalmers was released. On 16 July 2012 he signed a one-year contract with the club. Niven was ever present for the club in the centre of midfield with Craig Disley and helped play a part in the club's promotion and FA Trophy run in. Grimsby missed out on lifting silverware at Wembley Stadium having been defeated on penalties to Wrexham, and later lost out in the play-offs to Newport County. Town released Niven on 2 May 2013. On 17 July 2013 it was announced that Niven had dropped a further two leagues down by signing for Northern Premier League side Buxton. In 2016, he moved from Buxton FC to join Bakewell Town FC in the Hope Valley league. In 2008 Niven overcame a battle with Testicular cancer.