What does it mean if my chest freezer is sweating outside?

There may be a fault with the freezing mechanism. If the temperature inside is as it should be, no need to worry. That is if the temperature is registering -18 -22 C. Anything above these you may need to keep an eye on the use by date recommended by the food manufacture.

It usually only means that there is a high dew point outside the freezer (hot and humid) and the outside freezer temperature is lower than the dew point.