Do not use exFAT. MK11 writes cache data obsessively. exFAT on Switch CFW leads to corrupted game data within 2 weeks. Convert to FAT32 with 64k cluster size.
The base game cart or vanilla NSP is often on version 1.0. This is unstable and incompatible with the major DLC packs. You must install the latest update. mortal kombat 11 switch nsp update dlc work
Patches vs. DLC: Some releases provide a single large update that includes multiple fixes plus bundled DLC; others split patches and DLC. When updating, prioritize official title updates (to fix compatibility) before adding DLC content. Do not use exFAT
Open the tool and load your base NSP, update NSP, and DLC NSPs. Select the option to "Build Multi-Content File." mortal kombat 11 switch nsp update dlc work