There are a number of them, and most do a pretty good job.
A bit of an off the main path movie that is a favorite of mine is By Dawn's Early Light
...an HBO movie that is not perfect, but compelling. James Earl Jones and Powers Booth are very good!
I stumbled on this top 20 list: http://www.imdb.com/list/C2wHg4AOJGc/
Not movies, but two amazing books on the subject of nuclear weapons and warfare history are by Richard Rhodes:The Making of the Atomic Bomb
traces the history beginning with the key scientists and science early in the 20th century, covers the Manhattan Project exhaustively, and ends with the end of WWII. He utilizes extensive declassified documents of all kinds from the scientists, to Los Alamos, to the White House. It covers in great detail the firebombing campaign over Japan, the influence of General Curtis LeMay in that campaign, and the great difficulty and debate by many in high places in making the decision to use the weapon on Japan. It also includes a brutally detailed description of the horror in Hiroshima.Dark Sun: The Making of the Hydrogen Bomb
picks up where the first left off, covers Oppenheimer's departure, Edward Teller's influence, the weapon ("the super) development, the roots of the Cold War, the development of SAC and again, LeMay. This book ends about at the end of the Cuban Missile Crisis. The history of the weapons testing, LeMay and SAC, and the Cuban Missile Crisis will scare the crap out of you. We were lucky to have survived that era.
The good news is that we don't now have quite the capacity to make the planet uninhabitable nearly as quickly as we used to. With the last city killer-sized weapon, the B-53 recently dismantled, we are down to much closer to the Hiroshima size yield weapons. Today, the MIRV'd ICBM, SBM, SLBM, and ALCM nuclear arsenal is still a formidible threat to be reckoned with.
In reading these you learn maybe surprisingly that both the U.S. and Soviets realized by the late 50s that the weapons had become so huge and the ability to deliver so many so efficiently had grown to the point that the use of very few would render the planet uninhabitable. Was that enough to insure that we couldn't have gone to a full-on exchange during the Cold War? Unfortunately not since some like Generals LeMay and Power are said to have believed that nuclear war could be won with a preventative
(not pre-emptive) strike. Fortunately, by 1956 or so, LeMay believed that the Soviets had reached a point of parity and that a U.S. preventative
first-strike might not be successful unless there was some highly unusual circumstance that would give SAC a sizable strategic advantage. At that time, stategic nuclear strike policy changed to one of "Pre-emptive" strike or retaliatory strike. You will read that but once past the Cuban Missile Crisis, it seems that cooler heads began to evolve and come into positions of influence.
That's what I took from the books, anyway.
If you read these books, you will then enjoy watching both Fat Man and Little Boy
and Thirteen Days
. Both appear quite accurate, and the latter may have used Rhodes' books as resources since events depicted follow Dark Sun
very closely. Both movies cover a number of events briefly that will pass you by if you haven't read the books. Once you've read the books, you will catch them and appreciate.
But I get the OP's point. Two countries in the Middle East going to nuclear conflict would be bad enough. Could Pakistan and India stand down, or would they go for it, too? Would the Russians hold tight?
Scary stuff, for sure.