Update: Google Now in Nova Launcher is already enabled in the stable version, which can be downloaded from the Play Store from here!
One of the functions Most coveted of the Pixel / Nexus phones, is the possibility to invoke Google Now with a simple swipe to the left:
Until now, no other Launcher could imitate this functionality due to restrictions imposed by Google. However, Google recently changed its stance so that phone manufacturers could implement Google Now, with the Launcher of Xperia phones being one of the first. That's right, there is an API, a way for other manufacturers and developers to implement Google Now now. However, due to Play Store rules and limitations, this cannot be published on the Play Store.
Luckily, Nova has found a way to do it, and best of all, you don't even need the Nova Launcher Prime version to get it, the free version is enough!
How to integrate Google Now to Nova Launcher?
They need two things, apart from being in Android Marshmallow, onwards.
Download both APKs, install them and something important: disable infinite scrolling on desktop. Once done, restart (to improve performance), slide your finger to the left and Presto! Google Now in Nova Launcher!
I just tried it on multiple phones, including an S8 +, the LG G6, the Mate 9, and it has worked extremely well at all times. Being able to invoke Google Now from the left is one of the functions that is most missed when using a phone that is not the Google Pixel, so I think it is great to be able to activate it, now, on any Smartphone.
Hopefully we'll see other developers (like Action Launcher, or Evie, my current favorites) implement it soon!