In the Dune universe, when a laser weapons hits a shield, both are destroyed in a nuclear explosion reaction.
So instead of building nuclear weapons, wouldn’t it be easier to tie a timer and a “parachute” to a laser gun and drop it from orbit onto your enemy’s city?
IIRC, this is actually done at some point in the books.
Fremen setup some shields in the desert to punish the Harkonen for randomly firing lasers at the sand trying to smoke them out. Or something like that.
spoiler
You do remember correctly. Bashar Miles Teg at one point utilizes a variant of that technique. They mount pairs of shields and lasguns on anti-g platforms and use them as surprise tactical nukes in a battle against the Honored Matres. That is one of the many epic af moments in the Dune saga. I think I will have to read it for the umpteenth time now :)