Update: Looks like the Nougat update isn't quite rolling out yet, as the release notes seem to have been published prematurely. Motorola hasn't revealed a date for when the rollout will commence, but we'll let you know as soon as it does.
Just yesterday, Moto G4 Plus customers in Brazil started receiving soak test invites for Android 7.0 Nougat. Motorola is now announcing the official Nougat rollout to the Moto G4 and Moto G4 Plus in India, following which the update will be available to devices globally.
Motorola's release notes (via GSMArena) highlight all the new features in the Nougat update, including multi-window mode, changes to Android for Work, Doze on the Go, built-in Data Saver, improved notifications, and much more.
My Moto G4 Plus running Marshmallow and the July security patch shows that I'm on the latest version. It's likely the OTA will be delivered in phases. If you don't see it just yet, hang on. Nougat is coming very soon.