How It Will Change in the Future
You can see how nice has evolved in part depending on our changing opinions of the things that were labeled with it. Fussy dressers became popular, so the words used to describe them became compliments. From this we can predict the future path of nice by looking at one of the most notable groups labeled with it these days: "nice guys." If you aren't familiar with the term, welcome to your first day on the Internet, and pay special attention to the scare quotes I threw around the term. "Nice guys" is basically a self-applied term for dudes who identify themselves as nice above all their other qualities, perhaps to conceal that they don't have any other qualities.
"I might be ugly and dumb and repetitive and dumb, but I am at least fairly nice."
"I'll grant you the ugly and dumb thing, but are you actually that nice?"
Although, undoubtedly, there are many "nice guys" who are pleasant, well-meaning individuals, the label has become associated with some fairly sleazy creatures in the pick-up artist community, and there's now good reason to be skeptical of someone who describes himself that way. Extending this into the future, we can see that nice will soon turn into an adjective that means selfish, delusional, or generally something far less complimentary than it is now.
"If that's your best offer, I will tear you a nice new asshole. Don't fuck with me. I'm the nicest motherfucker you've ever met."