I think it would be cool if I could use these two mods alongside eachother. Currently, only the Nicer Skies sky shows. But it would be ideal imo to have the stars from the custom stars mod render over it. So I would have the amazing looking nebulas from Nicer Skies with the customization of the stars, night sky and moon from this mod. I'm not sure if this is possible or not but if not I'll probably just have to make a choice between the two.
P.S. I've also made an issue on the Nicer skies github similar to this one.

Modrinth link: https://modrinth.com/mod/nicer-skies
Github: https://github.com/ZtereoHYPE/nicer-skies