Google Assistant for Your Rooted Nexus Device
If you want to try out Google Assistant on your phone, give Get Assistant a try. This app tinkers with your build.prop, so you don't have to. It rewrites a couple of lines of code, which "tricks" Google into thinking your device is compatible for Google Assistant, and it's as easy a pressing a button. Once you dive into the app, it will give you specific instructions on how to install it and what to clear in order for the tweak to work. If you're feeling hesitant about this app messing around in your build.prop, not to worry, it will automatically save a backup of your current build.prop so you can go back to the regular Google Now on Tap. After trying it out for a couple of days, I can say that it works almost like the real thing, except the "OK Google" command, it will work but you will have to go through the process of recording your voice each time, besides that, the commands work, it sounds like the original Google Assistant, and it's quick.