A good card to check when there is an enemy Makoa is Barrier Reef (Link to Barrier Reef image + desc: https://paladins.gamepedia.com/Barrier_Reef) if he is running it at Lv 4 or higher, ignore the shield so that he has to wait longer for his shield.
There are not a lot of things you can do here. Use walls as cover and wait for a flank to kill Nessa is most likely the best solution Using his shield can block a few shots (You can do this if you are really close to capturing the point etc).
If a Grover is by himself, this can give any champion with decent mobility a chance to close the distance between them and Grover. The closer you get, the more damage you do and the less damage Grover does. Don’t forget about the vine though!