The Nubia Z17 came with its own Qualcomm Quick Charge 3.0 charger even though the phone supports Qualcomm Quick Charge 4+ technology that enables both USB Power Delivery and Qualcomm Quick Charge 3.0 charging.
Plugging in the Nubia charger to the Nubia Z17 using the USB Type-A to Type-C cable, we do not observe any USB Power Delivery Protocol transaction given the charger doesn't support USB Power Delivery.
Looking at the power graph, the Nubia Z17 starts off drawing current at 5 volts and eventually draws around 17 watts (5.9 volts @ 2.9 amps) from the charger when the phone is 7% charged. Since no USB Power Delivery based power contract is established, it appears that the phone is charging using Qualcomm Quick Charge with its own charger.