IMHO you went overboard with the grain/noise and got colored speckles which distract from a nice shot of autumn leaves and running water. You also need an apostrophe in "Nature's". I didn't mark down for the grammar. 8)
I have seen many images which relied on artifacts to depict grain. I like the fact that you did not grain the water on this one. You used selective sharpening, but I still don't care for the artifact look.
The overall effect is nice, although the grain does not ad as much as the rest of the process that gave this picture its earthy tonality. The only change I would make is t ensure that the grain was the same colour as its surrounding environment. That is the problem of digital grain that is not present in film grain.
Color noise is probably not going to do too well in this challenge because it doesn't look as appealing as the grain film gives you. Next time, if you want to try this again, select "monochrome" under the add noise filter. That may give you a better effect.