In front of an impartial audience, say 50% Muslim, 50% non-Muslim, it would be a matter of the utmost simplicity to defeat him in a debate.
He comes from an intellectual tradition where unquestioning submission to authority is the norm. Unfortunately, saying "it's written in the Qur'an, therefore it's true" does not count as a valid argument.
Let's take one of his points from a video posted earlier in the thread. He's answering the charge that Islam has a monopoly on terrorism, which is very easy to refute anyway.
He tries to show that the Qur'an utterly condemns killing by referring to surah 5 ayah 32, saying that if someone, Muslim or non-Muslim, kills any other human being, Muslim or non-Muslim, it is as though they have killed the whole human race. That's a pretty noble sentiment, but unfortunately it's not precisely what the Qur'an says. Read the verse, and not only is the point about "Muslim or non-Muslim" not mentioned, but there is an extra proviso:
Originally Posted by Qur'an 5.32
(Yusuf-Ali translation. I would use a better one but unfortunately I can't get any of the searchable Qur'ans online to work. What are the chances of that? It's never happened to me before.)
The part about "unless it be for murder or for spreading mischief in the land" makes what seemed earlier to be a noble sentiment much more equivocal, and makes it very clear how terrorists use the Qur'an to justify their actions. Whether or not someone is "spreading mischief in the land" is very often a matter of opinion: this could be why many Muslims disagree about the rightness or wrongness of terrorist actions.
Naik does mention this part as an afterthought, but only after he has completely misrepresented his own scripture in front of an applauding audience who don't seem to have even noticed.
If people think that's a good way to debate, I would recommend a strict diet of philosophy (Plato, Descartes and Russell are good places to start) to sharpen up their discriminatory faculties.
Please, people, don't fall for Naik's cod-intellectual propaganda. I thought this kind of approach had died out during the Renaissance, but, sadly, it seems it's still with us.