We use ODA Viewer and OdVisualizeViewer to open and visualize. nwd, .nwc and .nwf files. You need following archives: Kernel, BimNv, Visualize and VisualizeQt.
Unpack and extract them into the same folder, go to exe\vc15_amd64dll sub-folder and run OdVisualizeViewer, now you can open a Navisworks file.