When the Batman: Return to Arkham collection was rumored and eventually announced for the Switch, it was not released as individual NSP files (the file format for Switch games). Instead, the Arkham series arrived on the Switch in two specific bundles:
Pro-tip for modders: Always scan NSPs through a tool like NSC_Builder before transferring to your Switch. batman arkham city switch nsp update exclusive
If you are experiencing during the NSP installation? When the Batman: Return to Arkham collection was