The former Bolton and Gillingham midfielder, who competed in the top four tiers of English League football, replaced Steve Ward on the eve of the 2014/15 season.
And and he worked alongside manager Jay Saunders as the club won back-to-back promotions from the Isthmian Premier to the National League.
Chief executive Bill Williams told the club`s official website: “Nicky can be proud of the part he has played in one of the club’s most successful periods.
“As a club we’ve taken stock of the last two years and feel the time is right to make changes. It’s now up to Jay to set about making those.
“We thank Nicky wholeheartedly for all he’s done and wish him every success in the next chapter of his career.”
Saunders said: “Nick has been an absolute pleasure to work with and I cannot thank him enough for everything he’s done for me and the team over the last few seasons.
“My priority now is to get a new management team in place and continue building the squad for next year”.