Is there some way to setup PlatformIO so I can use it to debug WisBlock device application code?
I have been able to do it with other boards either natively or via SWD using an ST dev board as an ST-Link SWD go between.
I do not have access to a J-Link device so I think that is not an option unless I try to convert the ST-Link board to a J-Link, if that’s even possible.
The ST-Link on dev boards are usually designed for ST chips. You can still try it though but there is no guarantee to work. The best way still is to have a jlink and used it as the debugger for platformIO.
The ST-Link is a “high level adapter” which means its not entirely generic over all non-ST SWD targets, but the Nordic BLE chips are among those it is known to work quite well with.
As such this is ultimately mostly a problem of PC-side software and configuration. I’ve debugged Nordic BLE chips using an ST-Link as the interface with openocd and arm-none-eabi-gdb, but there may be a variety of hurdles to overcome in getting a particular project set up for that, if it is - as apparently indicated above - not an officially supported path.