I create a new C/C++ Project on MCUXpresso IDE, there is no Kinetis MCU when device selecting, as following picture.
IDE version is MCUXpresso IDE v10.1.1 [Build 606] [2018-01-02]
As per the supplied MCUXpresso IDE v10.1 User Guide, support for Kinetis parts is added by installing the SDK for the part / board that you are using.
As well as looking at the User Guide, the videos attached to this community also go through how download and install an SDK : MCUXpresso IDE
Regards,
MCUXpresso IDE Support