NSP stands for Nintendo Submission Package. It’s the official digital format Nintendo provides to developers and publishers for distribution via the eShop. When you buy a game digitally, your Switch downloads an NSP file encrypted with your console’s unique keys.
Use Deku Deals (deku.asksly.com) to track MK11 Ultimate price history. It drops to $19.99 every 2–3 months.
The "exclusive" part of your search likely refers to:
No legitimate "exclusive free download" exists. Any site promising one is distributing pirated NSP files.
Before discussing downloads, let’s appreciate why the Switch version is so sought after.
If you want "gratuita" but legal, here are real methods:
Buy a used copy from eBay, Mercado Libre, or Facebook Marketplace. Prices often fall to $15–25 USD. No DRM or online checks for single-player.