Correct wiring of Cortex-M 10-pin Debug Connector
nRESET and JNTRST do not fulfill the same purpose.

nRESET is full chip reset.
JNTRST is jtag reset, which is used for boundary scan.

The small 10 pin ARM SWD connector does not connect to JNTRST, that's a JTAG feature. You need the 20 pin version for that.

As also described in the manual of the ST Link V2, which has the 20 pin connector.

Note that NRST is always NRST.

nRESET is also optional. Only if you intend to disable access to SWDIO and SWCLK a full chip reset by the programmer is required.  



I often add a non-populated resistor in series with NRST to the programming connector to reduce risk of problems in the field. I can add this for prototypes, where it might be required. Production programming is not impeded by this.