娘 is clearly niang2, but 炮 is a multiple pronunciation character; it can be bao1 or pao2 or pao4 according to the dictionaries I consulted. I tried searching Baidu for "娘炮拼音" but didn't find anything. Thanks for any help!
Oh, get you a Taiwanese news (at 0:18 by the anchor, 0:58 by a student and 1:24, 1:56 by himself) about that, where it's pronounced as "niáng pào". I can tell that we use this word in mainland China too, here is the proof.
It refers to a sissy (a boy that other boys dislike because he prefers doing things that girls enjoy).
The answer is pao4 (the most common pronunciation)
如法炮製、炮烙 are pao2
炮羊肉 is bao1
When pronouced pào, it usually means artillery.
páo means burn or roast
如法炮製 is an idiom, means follow suit.
炮烙 is a ancient torture (stamp on someone's body with burning iron)
And bāo means stir-fry or drying
炮羊肉: stir-fry lamb
but in fact, bāo is not in common use.