It is based on a FLIP sim driven by noises and then color-corrected in Nuke and AE.
I originally wanted to approach Teun van der Zalm's nebulae looks and I'm quite happy with the result !
Feel free to give me your opinion, thanks for watching !
I also did this video some times ago, again a Houdini Nebula RnD video but another technique was used : the nebula was slice-rendered and colored exclusively in After Effects :