Two goals from Nkoto and another from Noah Ajayi made sure of the points on a rainy occasion throughout.
That result will help provide a huge boost heading into Tuesday's huge FA Youth Cup clash with Peterborough, with tickets still available for the tie.
FIRST HALF A solid run forward from Nathaniel Brown came next, with the winger getting the better of Henry Johnson, before also seeing his shot saved by Mair.
Jim Thwaites was the first player to try and help United ease into the game, with his curling shot after nine minutes palmed away by George Mair, with Mantato also denied on the follow up.