The science fiction story "The Cold Equations" by Tom Godwin tells of a pilot named Barton who is carrying emergency medical supplies from a starship to colonists on a frontier planet. He is piloting an Emergency Dispatch Ship, or EDS, which has a limited amount of fuel. He is fully prepared to jettison a stowaway that he discovers is aboard until he finds out it is an 18-year-old girl named Marilyn. Barton tries to do everything he can to somehow compensate for the extra weight, but in the end he has to eject the girl out into space to die because the ship is not carrying enough fuel for two passengers.
There are actually two conflicts in this story that can be termed "people against nature." The first, of course, is the conflict between Barton's compassion for Marilyn and the relentless "cold equations" that limit Barton's options in the immensity of space. Godwin has set the story up so that the lightweight EDS ship has such a limited supply of fuel that it cannot carry the extra weight of a stowaway all the way from the starship to the planet's surface. The author describes the inevitable physical law that must be followed like this:
A physical law had decreed: h amount of fuel will power an EDS with a mass of m safely to its destination; and a second physical law had decreed: h amount of fuel will not power an EDS with a mass of m plus x safely to its destination.
In this case, nature takes the form of a physical law that cannot be rescinded. The other conflict in the story that involves people against nature concerns the situation on the planet that Barton is on his way to help. It is a frontier planet, and six of the colonists have been stricken with a feverous disease carried by "green kala midges." The colony's own supply of medicine has been destroyed by a tornado, so Barton is bringing an emergency supply from the starship.