Old thread but it still comes up first when you search for importing FBX into MoI, so adding a simpler route for the conversion step. If you don't want to install MeshLab just to convert one file, https://furnimesh.com/convert/glb-to-obj turns FBX or GLB into OBJ in the browser with the scale intact, and then Pilou's _ImportOBJ route takes over from there exactly as described above. Michael's point still stands, what you get is polygon mesh reference geometry, not NURBS you can edit in MoI.