Spatial Audio plugin?

Depends on exactly what you mean by ‘spatial audio’ (Binaural, Ambisonics, Gaming VR formats etc). For binaural work, these are very nice indeed and have been using with Nuendo 10: DearVR Music, DearVR Pro, New Audio Technology Spatial Audio Designer. Both companies have gaming engines. I find that DearVR have truly excellent sound, verbs, and early reflections in particular; SAD also is nice, but the bussing, mixing and multiple speaker options are far more advanced.