Karbon uses the two-letter country code (ISO 3166-1 alpha-2) for country data saved to a Contact. This means that if you use a Zapier Trigger to update a Contact's country information, you will need to use the appropriate code.
Codes for common countries include:
New Zealand: NZ
South Africa: ZA
United Kingdom: GB
United States: US
For other countries, search the full list of two-letter country codes.