you’re able to help secure your Nintendo Account by enabling 2-Step Verification.
2.SelectSign-in and securitysettings, then scroll down to2-Step Verificationand clickEdit.
3.Click on2-Step Verification options.
4.ClickSend emailto have a verification code sent to the email address on file.
5.Enter the verification code from the email, thenSubmit.
6.Install theGoogle Authenticatorapp on your smart gear.
7.Use the smart unit app to scan the QR code displayed on your Nintendo Account screen.
8.A 6-digit verification code will appear on your smart unit.
Enter the verification code into the field under step 3 on the Nintendo Account screen, thenSubmit.
9.A list of backup codes will appear.
ClickCopyto copy all the codes, then paste them somewhere safe.
10.ClickI have saved the backup codes, thenOK.
source: www.techworm.net