Re: Idea
Only if your nuke is big enough to dig through the surface, techtonic plates and a fair bit of the core.
No problem. I suggest the Geostationary Orbital Nuclear Excavator. Plus there's some prior art, like the Sedan crater.
A long time ago in a small town far away I and about 4 other engineering hopefuls got very drunk and discussed this. It was rather weird.
IMHO, normal for engineers.. Although this may skirt dangerously close to civil engineering. But those sorts shouldn't be allowed to play with nukes. Remember, mechanical engineers build weapon systems, civil engineers build targets.
Also curious about the nickel/iron core. Like we've got one, why wouldn't Mars? And if Mars has one as well, what made it stop?