They have, yes, but in a deconstructed way. It is like a child had disambled the parts of a nose and spread them in the head of whales, and them they had developed or enlogated some pieces to connect them.
What has happened to the nasal bones and the maxilar bones is known as telescoping, the premaxilary and maxilary bones are told as having been extended at their rostral tips, while their caudal tips are pulled back and up over the frontal bone.
Here is a verygood illustration comparing the anatomy of cetaceans nasal and oral cavities with other mammals'.
http://what-when-how.com/
Somewhere between the front and upper part of the head there are the nasal opertures or nostrils, the blowholes or narines, two in the case of mysticetes and one in the case of odontocetes. They give pass to the nasal passages, basiclly muscular tubes which can have some valves that let the animal close them when is under water. These nasal passages are different from those of the rest of mammals in some respects, for example in that they are not covered in any moment by the nasal bone.
Then, the nasal bone has its own peculiarities. In the rest of mammals is a bone that projects itself from the frontal bone over the maxilar bones, forming the snout. But in cetaceans the nasal bones are very small and lie in depressions of the frontal bones, they are not roofing the nasal passages no more. Also, the roof of the mouth is not the floor of the nasal passage.
Of course the nasal passages function is to communicate the narine/s with the hole in the nasal bones.
Thus, what we know as the snout of the whales is formed by the maxillary and premaxillary bones alone, without the nasal bone.
If you want to learn more:
https://books.google.es/b
http://www.ncbi.nlm.nih.g
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