The file size for the Nintendo eShop version of Super Mario Odyssey will be just 5.7GB

Nintendo’s upcoming Mario title is launching this October and the official Nintendo website has revealed its file size and it’s surprisingly smaller than expected.  As always Nintendo have produced a game with bountiful content with a small file size. In the case of Super Mario Odyssey the file size is 5.7GB.
Super Mario Odyssey launches on Nintendo Switch on October 27th.
Source