Plants vs. Zombies Garden Warfare

When you are in a match of gnome bomb you will see a bomb symbol on your screen. go to that to see a smiling gnome holding a bomb about as big as him ready to blow stuff up for both teams pick that little guy up for arguably the easiest achievement in the DLC. If your teammate has the bomb wait near him for him to die and if an enemy has it kill him or wait for your teammate to do it

In addition to The Only DBry's solution:
At the beginning of the match you can gain a little advantage.
As a plant, use the peashooter and its ability Hyper or as a zombie use the engineer and its Jackhammer.
Since both abilities increase your movement speed, you have a better chance in reaching the bomb first.