Placing nuts in the freezer will prevent them from becoming rancid.
Rancidity happens when oxygen in air reacts with certain types of fats/oil.
Shelled nuts are susceptible to rancidity. (when unshelled nuts last longer... it is a seed afterall)
The more the fat is unsaturated the easier it will succumb to rancidity.
saturated fats (ex: coconut oil) are very stable
Highly polyunsaturated fats (ex: walnuts) are more susceptible.
When (quality) shelled nuts are packaged oxygen is removed and replaced with nitrogen (called control atmosphere packaging). They will not go rancid for lack of oxygen until opened. Occasionally an antioxidant chemical spray can also help that could be BHT, BHA, sulphites for example (read labels).
Rancid nuts smell like old oil paint (very chemical).
Rancidity breaks down the nutritional values of polyunsaturated fats.
So, if your pre-packaged shelled nuts don't last long once opened than you don't have a problem. If you buy in bulk for many months in advance, maybe freezing them is a good idea.
If you want a list of nuts according to their polyunsaturated fat content you can use this tool: Find foods by nutrient - NutritionData.com
enter highest in: polyunsaturated fats
per: 100g serving.
then within: nuts and seeds products
A list will be generated for you according to the most fragile to the least.
According to this list that I tried, cashews seems very stable having only 8g of polyunsaturated fats per 100g. No need to freeze.
Hope this helps?