Nom Nom Nom Achievement in Plants vs. Zombies
Nom Nom Nom10
Stop the horde using only the Sunflower, Wallnut, and Chomper on any level
How to unlock Nom Nom Nom
Easiest to do when you first unlock the Chomper while playing through the story mode. Just build sunflowers on the back two rows then have chompers in the two rows in front with a Wall-Nut in front of them.
If your chomper is taking to long to eat the zombie then you can dig it up and build another one where it was to restore it back to its original state ready to eat more zombies.
Heres a Video guide to show you how to do it:
If you missed out on doing this when you first unlocked the chomper you can also do this easily on level 1-1 of your 2nd playthrough of Adventure mode or on Survival Day.