… is a mountain range.

More nukes are surely going to solve that problem.

Presumably, you would not want to nuke an already existing oil pipeline.

Why not? Just fill the canal with oil instead of water and make it the new pipeline. This will also save money by not requiring ships to transport the oil. Or you can drive a ship filled with oil on the canal filled with oil, giving you twice the oil in one go. (certainly no insane troll logic here)

Real life ideas involving nukes to make canals through the desert aren't that much less insane, and also give a rough estimate of the amount and size of nukes required.