In theory since Nanite is able to simulate points at or near screen pixel density, tessellation and displacement should no longer be necessary, as you can build the detail right into the mesh.
Obviously if your workflow depends on using displacement maps on, say, hard surface geometry for high detail you’d have to move to a workflow where you’re baking that topology into the mesh beforehand, which does mean larger asset sizes, but the theory anyway is you shouldn’t need to tessellate in materials.
Currently Nanite doesn’t work with any vertex shader world position offsets at all, which I imagine comes down to instancing requirements (same reason per-instance vertex painting is not supported), although I suspect there will be changes to that eventually (if it’s technically feasible) since it’s usually needed to support foliage animation