The win extends our impressive unbeaten run to 10 league games.
It was a fast start from the City youngsters, and it was Nmecha who was the man leading our attack as the number 11 broke into the Brighton box before seeing an effort well saved by Carl Rushworth.
The following corner would lay the foundations for our opener, as Romeo Lavia latched onto the set piece before being fouled in the area, giving the referee no option but to point to the spot.
Nmecha stepped up and converted from 12-yards to score his second penalty in three games.
Maresca's side continued to pile on the pressure, and this nearly led to our second. A high press caused Seagulls centre-back, Jake Wakely to gift the ball to Sam Edozie, who then saw his deflected effort from 15-yards fall just wide of the post.
Despite a shaky start at the back the hosts made up for it at the other end, as Danny Cashman broke into the box, got across his man and curled his strike into the far bottom corner to level things up.
One man who began to liven up towards the end of the first half was league top goalscorer, Delap.
The forward came close five minutes before the break as he danced away from two Brighton men, before crashing his effort on the angle into the side netting.
Into the second half, and it was more of the same from City as our lead was nearly regained just a minute after the restart.
A marauding Edozie run down the right allowed the winger to pull the ball back for Claudio Gomes, who dragged his effort from five yards just wide.
In spite of the early missed chance we soon re-took the lead after Delap was fouled in the area, earning our second spot kick of the afternoon.
Delap himself stepped up and slotted his penalty into the bottom corner for his eighth goal in just four games.
After proving hungry in front of goal in the first half, Nmecha continued this in the second as just moments after regaining the lead the winger bussled his way into the box and struck an effort against the near post.
Minutes later Nmecha again proved too hot to handle, as he played a neat one-two with James McAtee before having his effort well saved by Rushworth.
As the game entered the final moments City's dominance continued as both Palmer and Nmecha had golden oppurtunties to add a third, however both fell just wide of the post.
A solid away performance was finally capped off in injury time as Liam Delap slotted home his second, and City's third from close range with almost the final kick of the game to mark yet another win for the Premier League 2 table-toppers.
HOW WE LINED UP
WHAT IT MEANS
The win extends our lead at the top of the Premier League 2 table to five points over Blackburn Rovers, leaving us on a total of 34 from 16 games played.
Our EDS return to action on Monday 8 March, hosting West Ham United at the Academy Stadium at 13:00 (UK).
News about Brighton v Man City
Watch EDS away at Brighton on CITY+
Manchester City’s Elite Development Squad (EDS) Premier League 2 clash away at Brighton will be streamed live on CITY+. Read more.
Highlights: Brighton 1-3 Man City EDS
City's Elite Development Squad (EDS) extended our lead at the top of the Premier League 2 thanks to a 3-1 win away at Brighton and Hove Albion. Watch more.