Nukes land where you are pointing, not the target.
So lets say for the sake of the argument, that maps had X,Z coordinates And you point at a ship that is at X 125, Z 303 and launch your nuke
And before the nuke land, the target moves aways from that X, Z position, the nuke will still land there. However, since nukes have a blast of 10 000 meters, its rare, that a non-corvette ship can escape that blast area. And important aspect of nukes, is that you can detonate a nuke upon reentry, by repressing "1". This help greatly with making sure that the blast touch the target on space map.
Also, the maximal range of nuke is false, your pointer won't show it, but a nuke can hit a target farther than its maximum range. It's just hard to do.
Missiles on the other hand auto-target were you're pointing at and have a maximum range. So if the target move beyond the maximum range, the missiles will follow it, until they either reach the target, hit a wall or reach their maximum range at which point they will explode.