No! Assuming you have a relatively new fridge, and assuming the biscuits/chips weren't wet when you put them in there, they will stay fresh and crisp for days. My mother used to do it.
Things generally only get icy if they are already wet and at a really cold part of your fridge. Fridges work on the same concept as air-conditioners, think about how dry things get in an air-conditioned environment. For more information check out 'howstuffworks.com', or go down to your local Google agency and request a pamphlet.