Hello,
The S32K144_64 can be selected by adding the S32K144 from the Component Library-> Processors tab and selecting the 64 pin variant in the "Add processor component wizard" dialog.
After the S32K144_64 is added to the project the PinSettings component will display a configuration switch confirmation button in the lower-right part of the view. Selecting Switch configuration will result in updating the available pins in the UI.
After adding S32K144_64 you can revert back to S32K144_100 by using context menu option "Component Enabled", in the Components View on the S32K144_100 Cpu.
Regards,
Iulian