Seems I accidentally deleted my original reply. See below:
The error you describe is sometimes shown by Eclipse when it is trying to write a file without permission. Some SDK installations will try to modify Eclipse plugins etc. and trigger this.
The core problem that leads to this is NXP installing MCUXpresso into `/opt` instead of the users home folder (like TI do with CCS).
As a workaround, you can try running MCUXpresso as root just to install the SDK. I've had success doing this or plugin installation when MCUXpresso was giving the same error.
And to the NXP team, please change the install location under Linux to the user's home folder. This will prevent this and many other problems (such as application note sample code not working because it expects the source files to be under the same parent folder as the IDE)