I have noted that SW4STM32’s debugger - or more accurately, the OpenOCD middleware it uses - has trouble recognizing any device connected to a USB3 host port. If I plug the same board into a USB2-only port on the same computer, it works correctly.
This problem was observed on several different PC’s all running Windows 7 64-bit.
The ST-provided “STM32 ST-Link Utility” application is able to see the STLink on a Nucleo board regardless of what type of USB host port it is attached to. The Atollic debugger also seems to recognize a board plugged into a USB3 port.
I think the problem might have to do with the version of libusb used to build OpenOCD. There have been some other applications I’ve seen that rely on libusb that fail to recognize or work with devices (that they would normally be able to attach to) if they are connected to USB3-capable host ports.
The first thing I’d do would be to get the STM32 ST-Link Utility (if on a Windows machine) and verify that you can connect to your Nucleo board using that. Also check that the two jumpers on the 4-pin header to the left of the ST-Link USB connector on the Nucleo board are both installed.