We are currently evaluating a nRF9160 for a consumer/industrial product. It does not have a built in antenna for GPS/LTE. There are detailed specs on designing for an external one from Nordic. Now normally, my understanding is in agreeance of what @tcrosley wrote FCC Certification? in this answer. If the module has a built-in antenna, or a connector for an external antenna (and you use a pre-tested one) you can be exempt from FCC testing as an intentional radiator.
The nRF9160 seems to be different. According to: FCC TCB
This grant is valid only when the module is sold to OEM integrators and must be installed by the OEM or OEM integrators. This module can only be used with a host antenna circuit trace layout design in strict compliance with the OEM instructions provided.
My take on that document is that as long as you follow Nordic's design doc's, and you don't exceed the power listed, you will be exempt from certification as an intentional radiator. That goes against all of my past experience and really doesn't make sense to me, since:
a host antenna circuit trace layout design in strict compliance with the OEM instructions provided.
is very open-ended and could easy be done improperly, causing the module to fail a test, if it was tested.