Chorley will go to Buxton top of the Evo Stik League and knowing three points will seal the title.
Second-placed FC United fought back from two goals down to win 3-2 to take the title to the final game of the season.
First half goals from James Dean and Darren Stephenson had given Chorley a 2-0 lead at the break, before second half strikes from Dean and Chris Almond sealed the three points.
It could have been an almost perfect start at a sunny Victory Park, Dale Whitham scuffed a shot at goal which found it’s way to Josh Hine but his shot was deflected wide of goal for a corner.
Marine’s Andy Fowler was then denied by an excellent Keil O’Brien sliding challenge , after the tricky winger got in behind the Chorley centre-half.
The Magpies then took lead after 17 minutes, Whitham whipped in a free-kick at pace which goalkeeper Callum Williams could only fumble and on hand was Dean who from six-yards sliced an effort into the bottom corner.
Victory Park was sent wild once again after 26 minutes, Dean saw his shot blocked but from the rebound he pulled the ball back across goal and on hand was Stephenson who lifted the ball into the roof-of-the-net.
Chorley continued to attack Marine but the visitors looked dangerous on the break, Josh Sumner, twice getting in behind the Chorley back line.
Roared on by an excellent crowd of 2128, Chorley had another effort on goal but Stephenson’s effort with his back to goal was comfortably saved by Williams.
The Magpies added a third three minutes after the interval, Hine pounced on a loose ball down the right hand side and after a moment of trickery he whipped in a pinpoint cross for Dean who headed the ball into the top corner.
Chorley goalkeeper Sam Ashton was called into action soon after the third Chorley goal, a ball was curled into the box and Marine target man Will Jones headed at goal but the onrushing goalkeeper made a smart block with his chest.
Dean, could have grabbed his hat-trick just after the hour mark but he failed to connect properly with an Alex Nicholson cross, skewing his effort wide of goal.
The game turned scrappy with Chorley seemingly happy to sit on their lead but as in the first half, Marine looked dangerous on the break.
Dale Wright then stung the palms of Ashton with a curling free-kick while at the other end Stephenson fired a tame effort straight at Williams.
Fowler then forced Ashton into a save at his near post before the Chorley stopper was called into action once again saving to his right from a Sumner free-kick.
With just two minutes remaining, Chorley added a fourth - substitute Chris Almond picked up on a loose ball and from 25 yards struck an effort low into the corner past a diving Williams.
Chorley : Ashton, Nicholson (Ross 70) , Cottrell, Teague (c), O’Brien, Roscoe (Almond 56) , Hine, Stephenson, Dean (Zibaka 90), Whitham, Jarvis.
Subs: Anderton, Grundy (gk)