The digital version of Xenoblade Chronicles 3D does not fit on the New 3DS' standard microSD card.
Nintendo includes a 4GB microSD slotted in every New 3DS and New 3DS XL. But you need to buy and upgrade to an 8GB or larger card to download the game.
"The download version of Xenoblade Chronicles 3D does not fit on the microSD card included with New Nintendo 3DS and New Nintendo 3DS XL systems," Nintendo notes on its official site.
"An 8GB or larger microSD card is required to download this game from Nintendo eShop."
Xenoblade Chronicles 3D is the first 3DS game that requires a New 3DS to play, due to the game's increased memory demands.
It's also the first 3DS game to specifically require more SD memory than included with the system as standard.
Nintendo and Monolith Soft's role-player originally launched for Wii back in 2010. This new port faithfully reproduces the game, although its optional Japanese voice track has been removed to save space.
Upgrading your microSD card is a fairly simple process, although you will need a Philips screwdriver to access the slot on a New 3DS XL.