Bags of chips, snack crackers, rice cakes are filled with nitrogen. This process of filling is called nitrogen flushing. Food packaged in stand up pouches and other packaging mediums is kept in an atmosphere of nitrogen because it does not react with the oils and other ingredients in food products. In this way, nitrogen prolongs the shelf life of food products and keeps them fresh for long. A study carried out by researchers at North Carolina State University in 2009 showed that nitrogen flushing extends the shelf life of whole milk powder for use in chocolate.
Despite the results of the 2009 research about the positive effects of nitrogen flushing on chocolate packaging, companies remain hesitant. A big reason behind that is the solid state of chocolate, which is able to bear human handling, unlike potato chips. Chocolate is more flexible and less brittle and doesn't break at the slightest touch.
Chocolate is usually transported and stored in a cold environment. It is kept away from other food products because it can absorb their aromas. So companies pay special attention to packaging, and they even try double or triple wrapping the chocolates. Puncture resistant plastic pouch bags can be used to package chocolate. Their multiple layer structure provides ample protection against humidity, dirt, and other environmental hazards. Humidity can cause white coloration on chocolate, which is unsavory.
Temperature is another big enemy of chocolate. For most chocolate products, temperatures exceeding 24 degrees Celsius and below 15 degrees Celsius are not good for chocolate's health. Therefore chocolate sold in the hot season (or hot areas) is usually kept in the fridge. Heat in the southern United States is sufficient to make a paste of a solid piece of chocolate and thus render it impossible to sell.
Because temperature and atmospheric protection are important, chocolate manufacturers usually spend a lot of resources in effective and creative food packaging and often skip nitrogen flushing for chocolates.
To conclude, even though it is possible to nitrogen flush and package chocolates, companies do not usually do that as they are more focused on protecting chocolate from the atmosphere through packaging, and keeping them in the right temperature range.