Complexity is no indication of a supernatural creator. Complex design is poor design; simple, efficient design is good design. So, if anything, the complexities of the universe are indicative of either no supernatural creator at all, or the creator being Azathoth.
That doesn't, however, make them coincidental. Rather, the complexities of the universe are self-causal. In other words, a planet forming and giving birth to life wasn't a coincidence, but an inevitability. Everything you see, everything you are, everything you can conceive of, is quite literally Stardust.