The Honduran international midfielder showed his predatory skills for Neil Redfearn's side, in a game which saw Paul Connolly and Lloyd Sam make their comebacks from injury and illness respectively - both featuring for just over an hour.
Nunez, who netted twice in each half, struck early on before adding a second on the half-hour following a surging run from James Baxendale.
The impressive Nathan Turner, Zac Thompson and Simon Lenighan went close to adding further goals before the break.
Andy Hutchinson reduced the arrears for the Red Imps early in the second-half before Nunez's cross eluded everybody before nestling in the net.
The schemer rounded off a fine afternoon's work by smashing home a half-volley just after the hour mark.
United: Gonzalez, Connolly (Snodin 62), Taylor, L Turner, Cardwell, N Turner, Sam (Booker 62), Thompson, Lenighan (Poleon 82), Nunez, Baxendale.