Battery and Charger Design for Xavier nx

Can you share with me this file fits for the Xavier NX, I only found it for the Xavier and TX2.

That will be released in future. You can check the docs of Xavier/TX2 for valuable help if necessary.

Do we have any estimation on when it will be released?
What are the main differences i should look at while looking on the TX2 file?

No ETA yet, but you can refer to the doc of TX2/Xavier as there should be no big difference.