@peter0425. Read the news sometimes. Dana already said that there will be no rematch because Amanda Nunes dominated Chris Cyborg. He would be creating a different storyboard if the fight was so close, however. But we have what we have hehehe.
Maybe if Cris Cyborg went on another winning streak then absolutely they will have to face each other again. Of course there is the money factor as well, if there's a potential to make good profits down the line then why not?
There was a video circulating lately that showed Cyborg take a nasty fall from a trolley, that was right before her fight with Nunes, so it's not impossible to think that the damage from the fall impacted her ability to fight.
I mean let's be realistic, Cyborg is an absolute monster, before this fight there was no reason to suspect that Nunes would dominate her in such a fashion. Since this was a relatively quick defeat, we can reasonably assume that Cyborg either had a bad day, or Nunes got particularly lucky. I really doubt that Nunes would dominate her again.
That being said, Nunes is also a beast, so I imagine the next fight will be more competitive.