I love how some folks jump to Trumps defense whenever something like this comes up. If he paid no income taxes in the last 15 years because he suffered a net loss of income, then the argument that he's a great businessman fails. Great businessmen make money, not lose it.
If the NY Times story does not seem completely credible, it is because they won't reveal their sources. However, if Trump says this information is wrong, he could sue the NY Times, (he's no stranger to using the legal system to his advantage). Of course, if he sued he'd have to prove they lied. How would he do this without revealing his tax returns to the courts.
Trump is his own spin-doctor. He'll do whatever it takes (like lie), to delay (indefinitely if possible), the truth being revealed about anything which paints him in a bad light.