There are, to some degree. I don't wanna talk too much about these things right now b/c it'd make them harder to use and they're my only serious tactical advantage ATM. But they suffer the same mechanical weirdness as artillery, only moreso. See forex how I'm not trying to use them to dislodge the forces around Burancon. I'll explain this much: the thing that makes them so lethal is their auto-kill chance (which IIRC is shared only with AA missiles). If you can't score a hit, though, the auto-kill test never comes into play.
I haven't tested shields vs. nukes b/c my experience w/them is mostly SP vs. AI and wildlife, but just based on the mechanics I do think they'd at the very least severely blunt their impact. There's a chance they'd melt immediately b/c shields are poorly tested (few people get to the tech level to use non-GR ones, and fewer still use them since the physical alternatives are so good), and the mechanics are significantly different than how other units work, but based on what they do I don't think they would. This conclusion is entirely based on me assuming the UI is correctly reporting how shields work mechanically, though, and I know about a year ago I dug into that, found it actually wasn't, and get a bug fix/shield buff implemented. It all comes down to whether the auto-kill check occurs when a hit depletes their armor by its value; it appears that counts as a miss, so it shouldn't right up until the shield is fully depleted, fails, and automatically dies. But again, their function is idiosyncratic and somewhat hard to understand, so it's not clear whether they would be subject to auto-kill checks from the first hit they take. I'd say they shouldn't, but I've been wrong about how they work in practice before, so...
I'm also not sure how shields interact with asset damage. It would make sense for Wide Area Shields to protect against artillery/nuke/aerial/conventional asset damage, but based on how THAT mechanic works I have a sneaking suspicion they don't.