There is no data to support the belief that freezing nylon hose makes them more durable.
Nylon is a fiber made from petroleum derivatives.
Properties such as strength and resistance to fatigue, or stress from flexing, and abrasion do not differ depending on temperature, particularly by the time nylon is in a finished article.
By then, the filament has been through processing that has heated, cooled and relaxed it, etc., so that there is not much left that can be done to it that will make a difference.
Du Pont, which developed nylon, suggested a possible source of the belief, however.
At nylon plants, comparison samples from each batch are frozen as a strict scientific control, to rule out any slight changes, such as shrinkage, that might take place in samples stored in a closet.
However, such changes would affect only the filaments themselves, not the finished product.