NUS provides DLC files, but the ticket is for purchased DLC. Homebrew can’t just download and run DLC without a valid ticket signed for your console.
When a console requests a game from the NUS, the server delivers the software split into multiple encrypted files: wii u nus
Click your choice. A download queue appears. The app pulls the .app , .h3 , .tik , and .cert files from nus.c.shop.nintendowifi.net . Once downloaded, the app automatically decrypts them using the title key. NUS provides DLC files, but the ticket is for purchased DLC