Your rather anticlimactic YouTube video shows the paleontologist patiently explaining to the interviewer how the skull was reconstructed from the existing fossils and what can be inferred through anatomical necessity and similar fossils. The nostrils must have been approximately where they were located in the reconstruction, as they were not anywhere else. Ultimately the exact nostril position does not determine the value of the fossil and is open to refinement if/when another specimen is found.
https://en.wikipedia.org/wiki/Cynthiacetus
https://en.wikipedia.org/wiki/Basilosaurus
https://en.wikipedia.org/wiki/Pakicetus
etc.