To unlock the Save Your Bacon achievement in Far Cry New Dawn, you will need to recruit Horatio the Wild Boar by completing the To Love a Boar side mission.
You can find the side mission at Elsinore Farm, which is north-west of The Pantry outpost.
Once you approach Elsinore Farm, take out the enemies in the area, approach the shed and shoot off the lock. Follow Horatio until he has stopped running and then pet him. When you have petted him, the To Love a Boar side mission will be completed and Horatio will be added to your roster, unlocking the Save Your Bacon achievement.