Do I have to use the Segger branded debugger to program over the 2-wire SWD interface (JTAG) of the Nordic-based modules?

Answer

Yes, any programmer/debugger that supports the SWD 2-wire interface and the Cortex M4F processor should work with the Nordic-based modules. You can find information about the memory map in the nRF5xxxx Product Specification under the Memory and NVMC sections.