You only have to log into NBC's app once across Apple devices
 

It's much easier to fire up This is US and SNL on iPhones and iPads now that NBC's iOS app finally works with Apple's single sign-on (SSO). You simply have to activate the feature on your device by going to Settings > TV Provider and typing in you...

https://www.engadget.com/2017/06/26/...gn-on-support/