The thing that almost everybody expected to come has finally come. Yeah. The Nokia X as an Android phone has been finally rooted modded to run custom Launcher, apps from Google (GApps) or even original Google Play Store.
While we have the Nokia X phone rooted, we can basically sideload any APK file, thus run it. Let's watch some screens of modded Nokia X running the original Google Now Launcher available on Google Play Store:
To do this, you need to root your Nokia X phone. This can be done using the Gandalf Exploit included in well-known rooting app called Framaroot (More info + download).
After that, install and download a root explorer, and finally install GApps. Download a special package by KashaMalaga@XDA (Thanks to him, we can do all of this stuff), extract and copy all the APK files included in the ZIP to /system/app directory and change the permissions to rw-r-r--.
After rebooting, download this package and install every single APK in the usual way.
After that, you should be able to run Google Play Store.
For more info, visit the original XDA thread.