$ sudo openocd -f "interface/stlink.cfg" -f "target/nrf52.cfg" -c "init" -c "flash info 0 "
Open On-Chip Debugger 0.11.0+dev-00062-g6405d35f3-dirty (2021-03-26-17:21)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
Info : auto-selecting first available session transport "hla_swd". To override use 'transport select '.
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD

nRF52 device has a CTRL-AP dedicated to recover the device from AP lock.
A high level adapter (like a ST-Link) you are currently using cannot access
the CTRL-AP so 'nrf52_recover' command will not work.
Do not enable UICR APPROTECT.

Info : clock speed 1000 kHz
Info : STLINK V2J17S4 (API v2) VID:PID 0483:3748
Info : Target voltage: 3.274766
Info : nrf52.cpu: hardware has 0 breakpoints, 2 watchpoints
Info : starting gdb server for nrf52.cpu on 3333
Info : Listening on port 3333 for gdb connections
Info : Unknown device: nRF51xxx (HWID 0x0000) 0kB Flash, 0kB RAM
Error: auto_probe failed

Another try:

$ sudo openocd -f interface/stlink.cfg -f target/nrf52.cfg -c init -c "reset init" -c halt -c "nrf52 mass_erase; reset; shutdown;"
Open On-Chip Debugger 0.11.0+dev-00062-g6405d35f3-dirty (2021-03-26-17:21)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
Info : auto-selecting first available session transport "hla_swd". To override use 'transport select '.
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD

nRF52 device has a CTRL-AP dedicated to recover the device from AP lock.
A high level adapter (like a ST-Link) you are currently using cannot access
the CTRL-AP so 'nrf52_recover' command will not work.
Do not enable UICR APPROTECT.

Info : clock speed 1000 kHz
Info : STLINK V2J17S4 (API v2) VID:PID 0483:3748
Info : Target voltage: 3.274766
Info : nrf52.cpu: hardware has 0 breakpoints, 2 watchpoints
Info : starting gdb server for nrf52.cpu on 3333
Info : Listening on port 3333 for gdb connections
Error: timed out while waiting for target halted
TARGET: nrf52.cpu - Not halted