Why is nitrogen gas used during the packaging of potato chips?
The Brits call them “crisps” for a reason. Three reasons at least for using 100% nitrogen:

Nitrogen contains no oxygen like air does which oxidizes the potatoes and promotes bacteria growth.
Nitrogen contains no water, which removes “crispness” from the chips and promotes bacteria growth.
Nitrogen inflates the bag which protects the chips, but, honestly, that could be done with air which costs less than pure nitrogen. But we know the downsides of air, don’t we?