The Texas Chain Saw Massacre

The description for the achievement is a little misleading because it implies you can trap Unlock Boxes and Bone Scraps as part of your basekit power. In reality, you're only able to trap those things with a maxed out power. You can only trap health items, the fuses and the valves in this regard.
Make sure to look around the map for these stations that have a bowl on them, you can use them to refill her power.

You must play as Sissy for this one and do the following:

Poison 15 items, such as fuses, valves, health items, lockboxes and bone piles. Also can poison main objectives like Generator and the Battery with a perk but you won’t need it.

Tricky part, she only starts with 3 poisons. You can pick up more on the bowls around the map, use up on the D pad to locate them if you’re having issues finding them. Realistically if you only go for that this should only take 2-3 matches.