One. One nuke could potentially disrupt it…but it’s not really advised for a few reasons:
If the conditions are still there that built up the storm, you’ve basically just nuked some wet air - if the pressure gradient remains and the waters are still warm, it very much could simply reform immediately
Dumping large amounts of energy into an active system might just turn it a different direction, unpredictably; you might steer a storm right into Miami that was just going to hit some empty marshes
Dumping large amounts of radioactive materials into a storm heading towards you might just end up making a giant somewhat radioactive hurricane, which is not great
Puerto Rico does not appreciate you dropping nukes just offshore