Conversion of vcard files to nbf file format

It doesn't seem to be possible to convert or otherwise import vCard contacts (.vcf) to Nokia backup (.nbf), simply because NBF backups are generated from the SD card, not the internal memory of the phone and as such does not contain address book, contacts and other data etc.

It is more than likely that you have been actually searching for vCard to NFB conversion, which would make sense as .nbf files contain phone backup, including contacts.

Open VCARD file    Open NBF file