This achievement cannot be missed and will naturally unlock if you follow mission objectives through the Baba Yaga DLC.
It unlocks relatively early in the DLC, a summary of steps below:
-You will be prompted when DLC is available to start and its objectives are highlighted by a pink outlined skull.
-Start DLC in Soviet Installation - Sawmill which is near fast travel point "Hidden Refuge Base Camp"
-Complete objectives Disturbance in the Sawmill, Chasing Grandpa, and Gathering Clues
-You now have the mission "Make the antidote" and need to collect 2 deer liver and 5 seed pods
-Fast travel to Logging Camp Base Camp and any 2 deer hunted and scavenged will provide livers. Fast travel to wilds for an alternate source of many deer.
-Near logging base camp, entering any caves marked by pink skull icon you will see vines with red flowers on walls. Most caves have 2, one has 3. Collect any 5.
-Next you will be prompted to go or fast travel to Copper Mill Base and find insecticide in a pink skull highlighted supply box.
-Once found you will unlock the achievement and be prompted to complete the next DLC mission.