If you want to backup or retrieve your Animal Crossing: New Horizons Island data via Nintendo's cloud save service, you can follow our handy guide on the subject:
Animal Crossing: New Horizons: How To Back Up Your Island Data
Note: In order to avoid players manipulating or duplicating data, Nintendo is rather strict when it comes to retrieving your ACNH island, stating that "Recovery is only available in situations where a Nintendo Switch console is lost or damaged".