I disagree. We are the absence of nature. Literally as a function of human life, we first remove nature and it's elements, then bring back in only that which we need and/or want to survive. We are the dark to nature's light. Sure, we are carbon-based lifeforms on this floating rock just like any other if you want to simplify it like that- except that all other species exist WITH nature just as a cog in a machine functions, so to does the many variables in the wild kingdom- but not humans. There is no equilibrium with humans on a grand scale, there is only conquest, dominance and unchecked expansion- more like a cancerous tumor on a living tissue than an organ functioning within a living organism so to speak. See, we don't feed back into the food chain, we don't serve any function to nature except to destroy it for our own needs (even if we consider ourselves conversationalists, if you had children you're adding to the problem by simple definition) and there is no limit to what we'll do for money, fame or even just a little slice of the world to call our own.
If you want to see how truly selfish the human race really is, you need to look no further than your local cemetery. Thousands of dead people nobody visits, cares about or even remembers at all- sitting there for eternity, taking up space just to do it and claim "your" place until the sun explodes.
So by definition, mankind is the opposite of nature IMO. We don't move among the trees, we cut them down and make a path. We don't live in nature, we cut it down and use it to build a structure to keep nature out. We don't create life or feed into a cycle, we just take. Hell, even after we die our bodies are left embalmed and of no value to even worms and such. We truly are the most selfish creature in the known universe and it shows every day.