The closest thing that comes to mind were the investigations into using nuclear-detonation powered propulsion for rockets, like in [Project Orion](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)).

Using nuclear charges to accelerate small masses would be extremely wasteful — each shot would cost millions of dollars, with little to gain from it (compared to ICBMs).

OK, actually, I had my coffee and remembered a single example of something like this.

It comes from a 1987 article on "Third-Generation Nuclear Weapons" in Scientific American by Theodore Taylor. This is of note because Taylor was one of the most prolific nuclear weapons designers in the US during the Cold War. Anyway, one of the schemes is a fixed-installation nuclear-powered cannon that would be used to attack satellites passing overhead. Screenshot. In the text he says:

An extremer possibility is the use of a relatively small nuclear explosion deep underground to accelerate very large projectiles through the equivalent of a cannon barrel. These so-called hypervelocity projectiles would reach velocities close to earth-escape velocity (about 10 kilometers per second). Appropriately shaped, compact projectiles can thus penetrate the atmosphere in a way that is somewhat analogous to penetration of the atmosphere by large meteorites. Such proposals were studied as long ago as the late 1950's as a method for placing massive loads of materials in space at relatively low cost.

The kinetic energy of, say, 10 tons of material moving at 10 kilometers per second is the equivalent of about 100 tons of TNT. This suggests that reasonably efficient use of a nuclear explosion with a yield in the vicinity of one kiloton could provide more than enough propulsive energy. If the "cannon barrel" were a few hundred meters long, the average acceleration of the projectile would be on the order of 10,000 times the acceleration of the earth's gravity, which is not beyond the strain-bearing capacity of a compact, high-density projectile. Subsequent fragmentation of such a projectile into solid chunks or liquid droplets could make it a highly effective weapon for destroying satellites or ballistic-missile warheads in space.

So that's the only comparable thing that comes to mind, other than Project Orion (on which Taylor worked), which I mentioned before.

You can't construct such a cannon. There is no steel or other material around that tolerates the pressures that arise when you'd fire such a gun.

It wouldn't make sense anyhow. This cannon would be humongously big, basically not movable and very hard to fire somewhat accurately. Furthermore you'd have your own soldiers in close proximity to the nuclear blasts. And what for? You'd have a tremendous reach with that cannon but precision would be abysmal. Like fire at Dallas and hope you hit Texas. That bad

There were cannons that shot nuclear warheads, such as the Davy Crockett but I guess you are aware of those.