The Nexus Player is a great device but installing XBMC/Kodi is not straight forward. Follow these steps we found on kodikwiz to get it installed and running in no time.

Setup your Nexus Player and connect your Google account.

Go to the Play store in your web browser on a desktop or laptop and install ES File Explorer to the Nexus Player.

Install Chainfire’s Sideload Launcher as well. It allows you to see the non-optimized apps you are installing from the main Nexus Player launcher.

Go to the Settings Menu on the Nexus Player and Navigate to the bottom and enter the Security & Restrictions menu. Enable unknown sources so you can sideload apps.

Download the x86 apk to your desktop from http://kodi.tv/download

Now you have a choice, either share the file from your computer or network share, or copy it to an USB thumb drive and connect it to the Nexus player with an OTG USB adapter cable (micro USB to USB connector.)

(USB Install) Enable developer mode: navigate to the About menu in the Settings, scrolling down to Build, and tap the select button repeatedly until a message tells you that you’re now a developer. Reboot the Nexus Player by unplugging the power cable and reconnect it. Once it has rebooted go to the new “Developer options” section in the Preference area of the Settings menu, and turn on the option for USB debugging. Connect the OTG cable and USB thumb drive

Through the Sideload Launcher open ES File Explorer.

Navigate either to your network share or the USB thumb drive.

Locate the XBMC x86 apk and answer yes to install the app.

Once installed XBMC works great, even the resource hungry skins work smoothly. Enjoy!