Be careful—if you read the title "Nothing Gold Can Stay" alone you might not even think of nature, but of money. This is a trap, because the poem is centered on the natural world and the types of gold we find there: the colors, the peace, the contentment. The poem covers leaves, flowers, sunrises, and perhaps the most famous garden of all, the biblical Garden of Eden. But that doesn't mean this is just your average look-how-pretty poem. Our speaker uses the imagery of nature to show his readers his thoughts about human life in general. This is a trend not just in this poem, but in many Frost poems. If you read enough of them, you get the feeling that we can learn everything we need to know from the natural world.
The speaker uses examples from nature to prove that many things in the world are transient, not just leaves on trees.
This poem isn't a nature poem in the slightest. It's one big metaphor, and the speaker's concerns are with the human world, not the natural one.