When running this with Bob's Logistics (which adds in a brass and titanium chest) if gives the error:

Failed to load mods: Error while running setup for entity prototype "steel-chest" (container): next_upgrade target (brass-chest) must have the same bounding box.

I checked and the Collision_Box and Selection_Box for those chests are the same size as the iron chests, so I added:
set_to_2x2_size(data.raw.container['brass-chest'])
set_to_2x2_size(data.raw.container['titanium-chest'])
to the data-final-fixes.lua file in BigChests right after the steel chest entry.

Now I'm receiving the error:

Failed to load mods: BigChests/data-final-fixes.lua:14: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
BigChests/data-final-fixes.lua:14: in function 'set_to_2x2_size'
BigChests/data-final-fixes.lua:29: in main chunk

I'm wondering if I have to go to Bob's Logistics mod and post a compat bug for this and see what I get in case the changes (which seems most likely considering there's not much I can do with the code for this) because I'm assuming the "pairs" string is an integral part of the script, but thought I'd ask here first. Thanks!