Code snippet from ReactNav application as featured in http://platypus.is/posts/4

createNestedNavDrawer.js

# App.js

...
const NestedNav = StackNavigator(
  {
    Landing: { screen: GreenScreen },
    Drawer: { screen: DrawerNavigator(
      {
        Home: { screen: TabNavigator(
          {
            Red: { screen: RedScreen },
            Blue: { screen: BlueScreen }
          },
          {
            tabBarOptions: {
              labelStyle: {
                fontSize: 20,
                marginBottom: 10
              }
            }
          }
        )},
        Purple: { screen: PurpleScreen }
      }
    ) }
  },
  { headerMode: 'none' }
)
...