You can easily export your chemical shifts and other project data to a NEF file by going to Project / Export / Nef File or using the keyboard shortcut EX. There is no need to include CCPN tags, as this information is not required by the BMRB. Start by deselecting all data elements and then include your Chain and Chemical Shifts which are mandatory. If you like, you can also include peak lists or restraint lists. Choose your file name and path at the bottom of the pop-up and click Save.
For more information on NEF files, see our NEF page.