Earlier when the UI was leaked by a user on NeoGaf, we saw how much free storage was on the device. The Nintendo Switch is marketed to have 32GB of storage and that does not account for the operating system’s size. Detailed in the picture below shows that there are 25.9 GB free on the Switch meaning that the OS takes up 6.1 GB.
If you are planning on buying The Legend of Zelda: Breath of the Wild digitally then it looks like you will not have that much remaining space on your console. Zelda takes up 13.4 GB of space and it will leave you with a little more than 10 GB remaining. Keep in mind that you will be able to expand memory via a micro SD card, so if you plan to go the digital route be sure to stock up on more cards.