Thanks to Blender's latest advancements in the EEVEE rendering system an updated 3D version of the Nebula Generator is now available Blender Market, free to existing users.
This 3D version will remain experimental for the moment as there are some strobbing artefacts whilst rendering animations in EEVEE, which although can be countered by high sample values, does impact performance.
The 2D version, available in the same bundle, is still available and has been updated for Blender 2.8 allowing greater control:
The file is documented with a set of how-to instructions and is free to existing users.
Hope you enjoy and do contact me via Blender Market for feedback as I continue to develop it.