Most miners generate nonces entirely at random, if I am not mistaken. That's inherently flawed, there are much better ways to generate a "low" hash value.
Actually, they iterate consecutively through the noncespace. (I think)
But hey, finding a needle in a haystack is in your favour searching consecutively if the needle is near the front of the haystack. Searching randomly, it doesn't matter where the needle is, it's random chance.