I think it looks good - you've got that cloudy nebula look down.
There are a couple of things you could consider, if you wish - the three "mountain top" shapes in the lower right don't seem to fit with the other shapes in my opinion. If they're meant to look like mountains (or something else: only the one closest to the center really looks like a mountain) then try to make them even more similar to such. And consider not having them all clustered in the same area. Or just make them more like the "rolling hills" in the rest of the image. I'm aware nebulas can form really strange shapes but these (especially the 2 in the foreground) don't feel natural to me.
The other thing is the darkness and the stars. I think the newest version is just a bit too black - the dark green of the previous version felt more dramatic. And while it seems stars would show all over the place (I did check som NASA photos) I still think it might be better to decide on one area (light or dark) to show them. I'd suggest to have them "only" in the dark areas (with some fainter/large ones still showing in lit up areas).
I've never painted a nebula though, that I can remember. So these are just things I'd try myself