Since iTunes 12.7, I have been manually loading the Nano runs into the 'Nike+ RunClub' app on my iPhone.
1. On the Nano go into the Fitness. On the left hand lower corner press the clock with the backward arrow surrounding it icon. This will pull up the runs by month. Pick a month, and then select a run. You will see the stats for the run.
2. On the iPhone go into the 'Nike+ RunClub' app. At the bottom of the screen near the left, press the three bars icon. This will show a screen that has 'HISTORY' tab at the top. Make sure 'HISTORY' tab is pressed (e.g, 'HISTORY' will be underlined then). With the tap pressed, the grand total miles or kilometers you have run will be showing on the screen. On this screen, at the top right there is a '+' icon. Press the '+'. A screen will come up that will allow you to manually enter what is on your Nano into the 'Nike+ RunClub' app. After you enter the run in there, it will sync to the Nike website.