Before you install google play, please root the Nubia mobile phone first.
Nubia Z11 Mini Root: http://www.nubiamobileshop.com/blog/nubia-z11-mini-how-to-root/
Nubia Z9 Series Root: http://www.nubiamobileshop.com/blog/how-to-root-nubia-z9-mobile/
Nubia Mobile Google Play Installation Steps:
1. Download and install this Google application downloader first(the apk file: https://drive.google.com/open?id=0Bw2ZA9BUygkBZ1JfeE9TS0RsTUE OR http://pan.baidu.com/s/1qW01Af6).
2. Connect wifi, find Google Play in it and download.
3. Click "Sure" on the pop-up
4. Download Google Service Framework; Google Account Management Program; Google Play Service; Google Play Store) (download icon at the bottom)
4. Install them in turn: google service framework -- google account management program -- google play service.
5. Install Google Play Store.
Note: During the four apps installation, you need install the other three apps first, then install Google Play Store, otherwise, the google play store can not work. If you installed Google play store first, just unload it and reinstall Google Play Store(only the Google Play Store app) from the Google Application Downloader, and it will be ok.
Why some users installed google play but can't work? Because you just installed Google Play but without complete Google service framework.