Hello Anabelle,
on G070RB, the UCPD IP is not available. So there is no interest in using UCPD Cube monitor.
The main interest of this tool is to see the USB Power delivery messages exchanges.
However, you could use this tool to read debug messages sent by your Nucleo, like you would use some "printf" with a console.
In recent STM32CubeMX versions (with STM32G0, STM32G4, STM32L5 MCUs), you have the possibility, once you have selected an UART, to use the TRACER_EMB module (in the Utilities part) and be able to see debug information with the help of UCPD cube monitor.

Then you can click on "Traces", at the bottom of UCPD monitor, and select your COM Port in the top right blue part.
(extract from UM2546)
Nicolas