Apps created with B4A works perfectly on NokiaX. Three of our company sales managers use department apps created with B4A on their NokiaX. Only apps containing Google Cloud Message (Notifications) ,Google Maps V1, V2 and Google Voice don't work without porting.
To check whether your apk is compatible with Nokia X, just drag and drop in space indicated here :http://developer.nokia.com/nokia-x/analyse/
If you don't have Nokia X, you can test apps on their remote device access here: http://developer.nokia.com/resources/remote-device-access