While nobody was expecting it to be small, the file size of FIFA 18 for the Nintendo Switch has been revealed to be 14301.53 MB (14.3 GB). While that might pale in comparison to 43GB require on Xbox/PS4, 14.3GB is just a little shy of the 32GB storage that comes with every Nintendo Switch. Therefore, for players downloading the game from the Nintendo Switch eShop, you might want to consider a microSD to go with it.
You can get more details about the game here.
FIFA 18 releases for the Nintendo Switch on 29 September 2017.