Thanks to the XDA user Nikhilkumar038, to bring Google Now cards on Jelly Bean or KitKat devices with Nova Launcher requires some technical skill to put into practice, but it is not difficult to follow. It does not require root access, all you need to decompile the Google Companion app to work on Jelly Bean or KitKat devices.
If you would like to get Google Now Cards with Nova Launcher on Jelly Bean or KitKat, all you need beta version of Nova launcher, Nova Google Companion app and a tool for modifying .apk files, such as APK Editor Pro, APKTool, etc. The procedure is somewhat simple, all you need to decompile the Google Companion app using tool like APK Tool or APK Editor, open the AndroidManifest.xml file and change the value of android:minSdkVersion=21 to android:minSdkVersion=19 (for KitKat) and android:minSdkVersion=16 for Jelly Bean. Then recompile the app and install it. If you are interested, follow Nikhilkumar038’s simple guide here. Does this feature useful to you? Let us know in the comment section below. (Source – XDA)