Earth-789 would be the comic multiverse name for Earth-89 if these comics are canon to it. Same Earth, different name in the comic multiverse to the live-action.
The Nolanverse doesn't take place on Earth-96 officially. I think it's a neat idea though. Gotham is referenced in Superman Returns. Certainly it could happen on Earth-96.
1 Earth 789 I think it's the extended version of the name earth 89, I don't see problems with the multiverse of the comics being the same as the one of the movies and the arrowverse.
The time line of earth 789 would be this.
1989 Batman
1992 Batman Returns
1993 Batman 89 comic
Following years: Joker revives and the events of that comic take place and eventually in 2019 the arrowverse thing would happen in which Joker is still alive and Batman caught him or maybe in this case it's another batman maybe Terry Mcginnis.
If you are wondering about the land of the flash , we can consider it as a variant of land 789 .
In total there are 3 earths.
Earth 97 = Batman, Batman Returns, Batman Forever and Batman & Robin.
Earth 89 = Batman, Batman Returns and the Flash
Earth 789 = Superman I,II,III,IV,Supergirl, Batman 89, Batman Returns, Batman 89, Superman 78 and CW Crisis on infinite Earths.
2 In Superman Returns the prequel when Perry White asks Lois for an article on superman, he mentions that maybe a friend from the Gotham Gazzette knows a thing or two about caped wonders (referencing Batman), a henchman of Lex Luthor seems to have worked for Joker (has a clown tattoo on his head), Gotham is mentioned in the news in Superman Returns and Joker is mentioned in Crisis on infinite earths.
And most importantly, this:
I think that in the same way that Superman Reeve and Batman Keaton coexist, we can assume that Superman Routh and Batman Bale coexist.
It's an idea I like, it would help explain how Bruce survived the bomb explosion in the dark knight rises and it would connect the dark knight rises well with crisis on infinite earths.