Two Sticky Bombs will down an Evie, hit your shots. If you anticipate being rushed put down a Grumpy Bomb. If you need to disengage use Poppy Bomb, then you need to finish the job before it finishes you.
If Evie uses her Ice Block to heal herself or to avoid damage, you can scatter Sticky Bombs around the Ice Block so you can hopefully kill her. Good reaction time is the key!
BK is one of Evie's best counters, if you run a BK vs Evie take the royal subjects talent (since the hitbox of royal subjects is so big it won't be hard to hit Evie).
If you see a Evie ice blocking stack some bombs near her and detonate them