Now, iPhone and iPad users with a cable or satellite TV subscription can sign in once with their TV provider credentials to gain access to content in the NBC app alongside all other supported apps that their pay TV subscription includes.
Single Sign-on is available in the United States only for these providers: Blue Ridge, Cable ONE, CenturyLink Prism, DIRECTV, Dish, Grande Communications, GVTC, GTA, Hawaiian Telcom, Hotwire, MetroCast, Service Electric, and Sling TV.
To enable Single Sign-on on iOS devices, open the Settings app and scroll down to "TV Providers" to sign in. From then on, when accessing a supported app that requires a cable subscription, the app will ask to use the saved sign-on credentials.
NBC's app, available for free on the App Store [Direct Link], also supports Single Sign-on on tvOS for the fourth-generation Apple TV.