The Live Variables functionality, as described in section 3.4 "LinkServer Global and Live Global Variables" of the MCUXpresso IDE v10.0.2 User Guide, is part of the "LinkServer" debug support - which functions when a "non-stop" debug connections is made.
Unfortunately, this is not available when using SEGGER probes (as mentioned in section 3.9.1, "SEGGER Differences from LinkServer Debug" of the MCUXpresso IDE v10.0.2 User Guide).
It is also not available using P&E Micro probes, though P&E provide an alternate mechanism via another view that their plugin provides (described in the PEMicro Blog).
Regards,
MCUXpresso IDE Support