> Also tried activating the debugger through MCUXpresso IDE, but nothing shows up.
This supposedly means you came across the installation of LPC-Link drivers during installing LPCXpresso. Is this correct ?
> This is what I'm seeing in device manager.
This looks like the driver is missing. Have you tried to install/re-install the driver from within the "device manager" ?
Have you tried another USB ports (on the same PC) ?
Have you tried another PCs ?