It seems that LG has now started pushing the Android 7.0 Nougat Software update to the LG G4 earlier than planned. However, the availability is only limited to the company's home country of South Korea.
The update can be downloaded via the LG Bridge app. You can also Install the update manually via sideloading KDZ files available for the F500S, F500L, F500K models.
For now, there's no information on when LG will start rolling out the update through OTA. We will let you know once it's available.
Download KDZ Files: XDA