Specifically with reference to nature rather than to other things... I would say that both poems show that Coleridge likes nature but also sees that nature can be violent and dangerous.
For example, in "Rime" Coleridge mentions the beauty of the sun as it rises and sets -- he makes it sound majestic. His description of the iceberg is similar. Yet at the same time, he has the ship punished by storms, which pursue it (it sounds like nature hates the ship).
In "Kublai Khan" the rivers can meander and be beautiful. But on the other hand, nature can be savage, with "ceaseless turmoil seething."
So it seems to me that Coleridge understands that nature can be beautiful and majestic, but very dangerous as well.
Concerning Coleridge's attitude toward nature, I'll tackle "The Rime of the Ancient Mariner" and let another editor handle "Kubla Khan."
The destruction and suffering experienced by the ship and the mariners is brought on by a senseless act of destruction. The ancient mariner kills an albatross for no good reason. He shows a terrible lack of respect for nature, for creation. All of creation possesses value in the poem, and the senseless destruction of any part of nature is a serious offence.
As the mariner says:
Farewell, farewell! but this I tell
To Thee, thou Wedding Guest!
He prayeth well, who loveth well
Both man and bird and beast.
He prayeth best, who loveth best
All things both great and small;
For the dear God who loveth us,
He made and loveth all.
Coleridge's respect for and love of nature is powerfully presented in his "The Rime of the Ancient Mariner." To phrase his views of nature in the poem in modern terms, we might say that Coleridge is suggesting that humans should be stewards of nature, not destroyers.
Coleridge’s personal life, was sexually chaotic. A perfect example of Coleridge’s spontaneity is found in "Kubla Khan," the short poem he began (but never finished) under the influence of a narcotic dream. Among Coleridge’s utopian projects was his failed "pantisocratic" community, based on free love and philosophical ideas. Coleridge’s life was catastrophically unsettled. Coleridge, left in his chaotic wake a collection of fragments, short works, and prolegomena. He compiled an autobiography—prose, in his case—Biographia Literaria, the biography of a literary sensibility. The work fuses Coleridge’s towering intellect, extraordinary powers of criticism, and feeling for poetry. Coleridge was, among his other achievements, a great theorist and critic of English literature. He died, wrecked by addiction, years before Wordsworth, in 1834. His greatest complete poem, The Rime of the Ancient Mariner, was composed during his collaborative years with Wordsworth.
"The Rime of the Ancient Mariner" is easy to read. It combines passion and intellectual force, psychological and social concerns, dramatic immediacy and imagistic subtlety, contemporary politics and ancient myth. Readers typically enjoy debating the meaning of the symbols—the shifting associations of the heavenly bodies, the alternating linkage of water with life and with death, and of course the setting at the threshold of a ritual of consecration. What does it all mean? Is the poem about primal sin or the slave trade, about tyranny and revolution or reverence for nature, about the aged Mariner’s sudden entry into adult responsibility or about his failure to mature? Is there a resolution or not?
"Kubla Khan" is likewise a psychodrama beneath its supernatural surface. Its "deep romantic chasm" is "girdled," seems to breathe "in thick fast pants," dances, emotes, and lives until it dies in the ocean. The imagery evokes a body, but only as what Coleridge calls a "phantom world" (he uses the phrase in his poem "The Picture" and quotes it as an epigram to "Kubla Khan"). And so the singer appears enchanted by his own imaginary landscape. "Kubla Khan" thus proves to be a portrait of a haunted mind, thrown between the extremes of ﬁre and ice, ecstasy and agony, and drunk on "The milk of Paradise"—a period name for the opium to whose effects Coleridge’s preface attributes the poem.