Avoid it. Extension cords can overheat and cause a fire risk.
If you must use one, three non-negotiable rules apply. Use only an extension cord with a grounding plug. The cord's marked rating must be equal to or greater than the ice maker's rating (120V, 60Hz, 105W). Position the cord so it does not drape over a counter where it can be pulled on by children or cause a tripping hazard.
The proper setup is a dedicated, grounded wall outlet. No other appliance should be plugged into the same outlet. Ensure the plug is fully inserted.
Heads up: Do not operate the appliance with a damaged cord or plug. If the supply cord is damaged, it must be replaced by the manufacturer, its service agent, or a similarly qualified person to avoid a hazard.