Did you forget what we were discussing? They don't need to carry two. One is enough for 150 rations. Don't forget goliath barbarian was noted in the OP. A early as post 5 there has been a steady chant of just enforce container sizes & backpacks only hold 20 pounds& there has been quite a lot of discussion about how that doesn't solve anything because more & bigger containers like the 30 pound sack & 300 pound chest since.Sure. A 20-Strength goliath barbarian can carry two mostly-full chests. And have no hands left to do anything else. If the goliath wants to act as a pack mule.
I mean, sure, my firbolg was fine with dragging a loaded sled back in our Icewind Dale game, because we wanted to get the sled back to town and we didn't have any sled dogs or other pack animals. I wouldn't want them to be the party's pack mule though; they're not that kind of person.