For Sonic Frontiers on Nintendo Switch, "NSP" refers to the digital file format used to install the base game, updates, and DLC on modded systems. The latest version typically includes the Final Horizon update (The Final Horizon), which adds a new story path and playable characters like Amy, Knuckles, and Tails. Installing Updates and DLC (NSP Format)
To get these working on a modified system, you generally need to combine the base file with the update and DLC files.
Essentially, users are looking for the complete collection—the base game, the new DLC waves, and the latest performance patches.
Despite being the most technically demanding Sonic game to date, the Switch version offers a complete open-zone experience: Nintendo Switch NSP Combination Install Tutorial
Which one should I provide?
What This Means for Sonic Fans