In the latest build (v2019.10.11.0022) we have added a new experimental setting at the bottom of the web UI that you can use to enable support for local NBC, ABC and FOX stations.
(NOTE: This feature will not work for everyone- it depends on your provider and on your location.)
NBC: Should work in almost any US city. Check nbc.com/live to see if you can stream your local NBC station.
CBS: Not supported. Local CBS stations are not available through just TV Everywhere login, because CBS wants you to use CBS All Access.