If you own a legitimate copy of Mortal Kombat 1 and wish to dump it to an NSP for backup (or have a modded console running Atmosphere), the installation process is standard:
Stick to PC or console. The input lag on the Switch version (even via OLED docked) is roughly 6-7 frames higher than on PS5. You will lose online matches due to hardware constraints, not skill.
Stay sharp, fighters. "Get over here!" — responsibly.
Standard DLC comes in —tiny files (usually 1 KB to 10 MB) that toggle the unlock flag in the game data. If you have a legitimate NSP of the base game but lack the DLC tickets, the characters will appear greyed out. The "Mortal Kombat 1 NSP + Unlocker" Scene In the console modding scene, you will often find releases labeled "Mortal Kombat 1 NSZ (Unlocker included)." These packages bypass the requirement to connect to Nintendo’s servers to verify purchase. Be warned: Using unlocker NSPs for DLC you haven't paid for is a violation of Nintendo’s Terms of Service and can lead to console bans if you go online. How to Install Mortal Kombat 1 NSP on a Modded Switch Disclaimer: This information is for educational purposes regarding legitimate backups and homebrew. Modifying your console voids warranties and breaches Nintendo’s EULA.
It is legal (under specific DMCA exemptions in the US) to format-shift your own game. If you bought Mortal Kombat 1 on a cartridge, you are allowed to dump that cartridge to an XCI and convert it to an NSP for convenience to avoid carrying the cart. However, sharing that NSP file online is illegal distribution.