Nature is aligned with society, and, to some extent, chaos in Of Mice and Men.
This is true, at least, in the sense that the men in the novel take shelter from the harsh realities of life within the literal confines of the bunkhouse and within the figurative protection of a shared dream. They do not take shelter in nature or seek to go outward to explore or build.
The forces which oppress the characters effectively boil down to a financial powerlessness brought about by a lack of resources and a lack of real upward potential. Society, like nature, has provided these men with nothing they can call their own.
Though it is tempting to see nature as a positive element in Of Mice and Men due to its apparent role in the dream shared by George, Lennie, Candy and Crooks, that dream is the only place in the novel where nature is given any positive attributes. Everywhere else, nature is either a place to run when trouble has struck or a wide-open space wherein the men in the book have no place of their own, no ownership and no power.
At the outset of the novel, the brook and the surrounding hills are presented in somewhat idyllic language, but quickly the identification of nature with escape and trouble is made. Nature is tied to the drainage ditch where Lennie and George had to hide. Nature is the desperate refuge that Lennie says he will seek out if George doesn’t want him to stay around.
As George says at that time, Lennie would die in the wild. And he does.