I am generally sympathetic to Iran, particularly after the 1953 Mossadegh incident where the Western colonialist corporate petroleum intelligence interests had its democratically elected leader assassinated in order to install a Shah, but no, Donald Trump is going to build a wall against Iran and make Iran pay for it.
Is it possible to change Chess Federation if I don't have the Nationality?

No, @DeidreSkye, that isn't true. How do you even "take the nationality" anywhere? Alekhine was Russian, did he take the French nationality? Did he do it accidentally, by sipping from a glass of good Burgundy? I WILL NEVER DRINK FRENCH WINE AGAIN; I FEAR THAT IT WILL VITIATE MY AMERICAN NATIONALITY!

Wesley So is not an American citizen, Naidich is not Azeri, etc etc...

Lookie here, I can play for whatever country in the world I want to. I can play for Mali; that's where Timbuktu is. This reminds me of a hilarious story from back when I did divorce cases. My client (the husband) was a total a-hole, and I knew in advance that he was going to fire me as his lawyer. I mailed all of his non-essential documents, the ones that could easily be reproduced at ten cents a page from the court file, to...
Chamber of Commerce
Timbuktu, Mali
...and when he came to my office to retrieve his file, he asked me, where are the pleadings and motions, and I told him I mailed them to Mali, and he roared WHO THE PHUQUE IS MOLLY? and I responded evenly "Mali is a country in Africa, it's where Timbuktu is." Yes, I had a loaded sidearm in my desk drawer that I would have cheerfully used on him if he had cut up rough; yes, Africans in crude dwellings reviewed the divorce file to see how we do it California-style, and undoubtedly yes, some of them can beat me in chess.

Earlier last year I got a FIDE rating, and I got asked what Federation I chose to represent, so I take it you can represent any federation you want. I'm representing the USA according to FIDE.

Is it possible to change Chess Federation if I don't have the Nationality? I would like to play for Iran.
https://ratings.fide.com/fedchange.phtml

Thanks alot!! They dont say anything about Nationality I will ask them thanks
They don't need to. If the host Federation wants to allow you to play under their flag, pay the fees or pass them on to you, they can.

Can I play for Iran without passport and not living there??
You would have to ask their federation officials.

But I don't think that flag exists here. ;-;

So for me its not possible? Who decides that?
Only their chess federation can help you or answer your questions about it with authority.
Is it possible to change Chess Federation if I don't have the Nationality? I would like to play for Iran.