Incubating stars is a dangerous art and must be done carefully. To create a star in this new version you first need a Star Base:
Than compress it with obsidians to create a Star Core:
Now, add some glowstones with some enderperls to create an Unstable Star:
Take really care because this star is really unstable!
To make it stable, put it inside a furnance and you'll create a Star:
Finally, go to nether and use your star (right clicking it) and if you are lucky it will become a Nether Star (but if you are not lucky it will break in parts)
I'm not a boring guy, ask me and I'll probably allow you to include it in your modpack. But ask me first.