Switch owner? Go enable two-factor authentication for your Nintendo account

Multi-Factor Authentication (MFA)

Linking to a Nintendo Account, Nintendo Switch Support

How to Enable Two Factor Authentication on Nintendo Switch

Got Yourself A New Nintendo Switch? Do These Things First

How to Enable Two-Factor Authorization on Nintendo Online Accounts - Nintendo Switch Guide - IGN

How to Set up Nintendo Switch Two-Factor Authentication

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How to get your Nintendo Account working on multiple Switches at once

How to set up Nintendo 2FA on your Switch account

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Multi-Factor Authentication: Who Has It and How to Set It Up