The nRF52840 isn't tested for this. Certification of a device can only be done for a complete module with integrated antenna. The nRF52840-DK doesn't need FCC certification but CE is always needed. The closest ETSI standard to the ANSI C63.27 should the immunity test, part of ETSI EN 301 487: 0066.372254-04 TRF EMC (nRF52840-DK).pdf
