You'll see that the armor is just a large breast plate, literally. Since this appears to be too small for her, Ellie will have you search around the backside of the house in a green highlighted box.

"This heavy-duty body armor features full-size high tensile strength ballistic plate to the front, rear and sides for maximum protection against large-caliber firearm projectiles and high ...

Looking for the best Monster Hunter Wilds armor? These sets are some of the greatest you can grab to destroy monsters and make each hunt a breeze.