Despite Android 7 has been launched almost a year, Android smartphones still suffer from large fragmentation as most vendors has yet to push new firmware updates to these consumer. After multiple request for LG to release update, LG has finally bring the Android 7.0 firmware online.
You can search up your model online for the latest update. Alternatively, one XDA developers has provided few mirror links for LG G4 Nougat update for model F500K, F500L and F500S. Although LG has yet to push the new firmware through automated OTA update, you can still upgrade your G4 manually.