This is how to import the import autocomplete into Outlook 2013

1. Locate the .nk2 file from the older version of outlook
2. Copy this file to %appdata%\Microsoft\Outlook and make sure it has the same name as the Outlook profile it will be imported into
   • Click "Start" and then click on Control Panel
   • Double click on "Mail"
   • In the "Mail Setup" dialog box, click show profiles
3. Click "Start" and then click "Run"
4. In trhe box type "outlook.exe/importnk2" and click "OK"

Note that the .NK2 file is renamed to .old after import so you will not be able to re-import

https://support.microsoft.com/en-us/kb/2806550