The gas you're thinking of is nitrogen. It's not actually to stop the crisps from getting squashed, but to prevent them from getting crushed and breaking.

Here's why:

* Protection from Oxidation: Nitrogen is an inert gas, meaning it doesn't react easily with other substances. This prevents the crisps from oxidizing and becoming stale.

* Preservation of Flavor: The nitrogen keeps air, which contains oxygen, away from the crisps, preserving their flavor and freshness.

* Crispness: Nitrogen helps to keep the chips crunchy and prevent them from becoming soft and soggy.

So, while the nitrogen gas isn't directly stopping the crisps from being squashed, it plays a vital role in their freshness and overall quality.