Two things I have against disaster movies in general and nuclear war movies in specific...
1 Despite the movies showing rape, pillage and everyman for himself. Experience such as 9/11 (and even Katrina) showed people are usually willing to help people. In the case of 9/11 too many people stayed behind helping the slow rather than getting out when they had the chance. When all those folks needed to get off the island, most merchant vessels created an emergency ferrying service without being asked, and without any gov't direction.
2 The impact of radiation and fallout always seems to be projected as the end of the world. "Nuclear winter" and unregenerate bleak landscapes are the tradition. But having been to Hiroshima and seen the trees that survived and regenerated, it makes me skeptical of that vision.
This is why I will never be a good story teller. I would tell an upbeat apocalypse.