spherical cloud so quickly I doubt you would be able to see it. Shocks in rigid materials tend to travel at something like 10 km/s, shock induced damage would likewise be immediate. Slower effects could occur as the air pressure inside blasts apart the weakened hull or blows out the shattered chunks, or as transient waves propagate through the ship's structure, or when structural elements are loaded so as to shatter normally rather than through the shock. Escaping air could cause faintly visible jets as moisture condenses/freezes out - these would form streamers shooting away from the spacecraft at close to the speed of sound in air - NO billowing clouds.
Luke Campbell===Nuke vs. Spacecraft===
Dr. John Schilling describes the visual appearance of a nuclear strike on a spacecraft.
First off, the weapon itself. A nuclear explosion in space, will look pretty much like a Very Very Bright flashbulb going off. The effects are instantaneous or nearly so. There is no fireball. The gaseous remains of the weapon may be incandescent, but they are also expanding at about a thousand kilometers per second, so one frame after detonation they will have dissipated to the point of invisibility. Just a flash.
The effects on the ship itself, those are a bit more visible. If you're getting impulsive shock damage, you will by definition see hot gas boiling off from the surface. Again, the effect is instantaneous, but this time the vapor will expand at maybe one kilometer per second, so depending on the scale you might be able to see some of this action. But don't blink; it will be quick.
Next is spallation - shocks will bounce back and forth through the skin of the target, probably tearing chunks off both sides. Some of these may come off at mere hundreds of meters per second. And they will be hot, red- or maybe even white-hot depending on the material.
To envision the appearance of this part, a thought experiment. Or, heck, go ahead and actually perform it. Start with a big piece of sheet metal, covered in a fine layer of flour and glitter. Shine a spotlight on it, in an otherwise-dark room. Then whack the thing with a sledgehammer, hard enough for the recoil to knock the flour and glitter into the air.
The haze of brightly-lit flour is your vaporized hull material, and the bits of glitter are the spallation. Scale up the velocities as needed, and ignore the bit where air resistance and gravity brings everything to a halt.
Next, the exposed hull is going to be quite hot, probably close to the melting point. So, dull red even for aluminum, brilliant white for steel or titanium or most ceramics or composites. The seriously hot layer will only be a millimeter or so thick, so it can cool fairly quickly - a second or two for a thick metallic hull that can cool by internal conduction, possibly as long as a minute for something thin and/or insulating that has to cool by radiation.
After this, if the shock is strong enough, the hull is going to be materially deformed. For this, take the sledgehammer from your last thought experiment and give a whack to some tin cans. Depending on how hard you hit them, and whether they are full or empty, you can get effects ranging from mild denting at weak points, crushing and tearing, all the way to complete obliteration with bits of tin-can remnant and tin-can contents splattered across the landscape.
Again, this will be much faster in reality than in the thought experiment. And note that a spacecraft will have many weak points to be dented, fragile bits to be torn off, and they all get hit at once. If the hull is of isogrid construction, which is pretty common, you might see an intact triangular lattice with shallow dents in between. Bits of antenna and whatnot, tumbling away.
Finally, secondary effects. Part of your ship is likely to be pressurized, either habitat space or propellant tank. Coolant and drinking water and whatnot, as well. With serious damage, that stuff is going to vent to space. You can probably see this happening (air and water and some propellants will freeze into snow as they escape, BTW). You'll also see the reaction force try to tumble the spacecraft, and if the spacecraft's attitude control systems are working you'll see them try to fight back.
You might see fires, if reactive materials are escaping. But not convection flames, of course. Diffuse jets of flame, or possibly surface reactions. Maybe secondary explosions if concentrations of reactive gasses are building up in enclosed (more or less) spaces.