Nike states in the change notes:
To connect your Nike+ account with Google Fit, upgrade to the latest version of the Nike+ Running app (v1.5), and follow the automatic connection prompts. Connecting to Google Fit is optional and may be turned on/off in your application Settings.
The new update to Nike+ Running also adds compatibility with the recently launched Samsung Gear S smartwatch. Are you currently using Google Fit and if so what are your first impressions?