Place your Sonic Frontiers US base file (NSP or XCI), the latest Update file, and the DLC NSPs onto your Switch's SD card.
Your keyword also includes "dlc update," which are crucial for getting the complete Sonic Frontiers experience. The game is designed to be regularly expanded with new content, both free and paid, to keep the adventure fresh. Here are the key updates and DLCs: sonic frontiers switch nsp xci dlc update us