In the small town of Rockwell, Maine in October 1957, a giant metal machine befriends a nine-year-old boy and ultimately finds its humanity by unselfishly saving people from their own fears and prejudices.
This movie contains 27 potentially triggering events.
spoiler: the climax is resolved by the Iron Giant flying into a nuclear bomb so it wouldn't kill the humans. However, we learn in the end that his body wasn't completely destroyed and he's reassembling himself
a character is given laxatives without his knowledge. It's shown that he makes it into the bathroom, an outhouse, or a bush each time he has an emergency.
the Iron Giant gets stuck in electrical wires and gets electrocuted for several seconds, but this is an accident, not something that someone else caused to happen
No, but there is a moment where there is threat of a nuclear explosion and the villain is kept from trying to flee so he can "die for his country like a good soldier".
The Giant can be interpreted as having a condition resembling PTSD, especially in the extended cut of the movie where he has nightmares about his military service.
At the end of the scene by the lake, when the Giant inadvertently causes all the water to cascade out of the lake, the camera is briefly "underwater". (But not actually underwater, because it's all animated.)
The whole movie is about the threat of nuclear holocaust. A nuclear missile is launched directly at a town full of people, who become scared for their lives. The bomb does go off but with only one casualty.