Is it the compressor that’s loud? You can’t change the compressor. Check for a vibration by shifting things around. Not the contents, push on different spots on the cabinet or push the compressor and see if the noise is the same.
It could be the rubber mounts the compressor sits on. Over time the heat from the compressor makes them hard. Make sure none of the copper lines are touching each other. If the legs are are adjustable try leveling the chest.