I finally found the Nikon announcement from late August that Big Sur is currently not supported, still no update as of today early December.
After some research I found another solution from a company technique, the name of their software is Webcam tool for Nikon. It works well, however it seems that either the Nikon or the driver is a bit finicky. The camera has to be connected to the computer, connecting to a hub like CalDigit on a MPB16 did not work. Also, long USB cables lead to a number of different connection errors and crashes. However, once I used the Nikon USB cable (with a ferrite at the micro USB connector side), the software works well. Limited to Zoom only, FaceTime or Skype do not recognize the webcam driver on macOS Big Sur.