The tournament's minnows, ranked 118th in the world, won through in dramatic fashion in their quarter-final against Tunisia.
Equatorial Guinea were trailing 1-0 before Javier Balboa netted a 90th minute penalty to take the game to extra time - and they won through in the added period with Balboa scored his second of the game.
The game ended with players and officials from both countries confronting each other as Equatorial Guinea fans celebrated on the pitch.
Nsue's team now face Ghana in the semi-final on Thursday.
Congo DR take on Ivory Coast 24 hours earlier in the other semi-final.
The final takes place on Sunday with the third-placed Play-Off on Saturday.