Does nihilism about ordinary things help us out with puzzles surrounding maximal properties and the problem of the many? It's hard to see how.
First, maximal properties. Suppose that I have a rock. Surprisingly, there seem to be microphysical duplicates of the rock that are not themselves rocks. For suppose we have a microphysical duplicate of the rock (call it Rocky) that is surrounded by extra rocky stuff. Then, plausibly, the fusion of Rocky and the extra rocky stuff is the rock, and Rocky himself isn't, being out-competed for rock-status by his more extensive rival. Not being shared among duplicates, being a rock isn't intrinsic. And cases meeting this recipe can be plausibly constructed for chairs, tables, rivers, nations, human bodies, human animals and (perhaps) even human persons. Most kind-terms, in fact, look maximal and (hence) extrinsic. Sider has argued that non-sortal properties such as consciousness are likewise maximal and extrinsic.
Second, the problem of the many. In its strongest version, suppose that we have a plentitude of candidates (sums of atoms, say) more or less equally qualified to be a table, cloud, human body or whatever. Suppose further that both the sum and intersection of all these candidates isn't itself a candidate for being the object. (This is often left out of the description of the case, but (1) there seems no reason to think that the set of candidates will always be closed under summing or intersection (2) life is more difficult--and more interesting--if these candidates aren't around.) Which of these candidates is the table, cloud, human body or whatnot?
What puzzles me is why nihilism---rejecting the existence of tables, clouds, human bodies or whatever---should be thought to avoid any puzzles around here. It's true that the nihilist rejects a premise in terms of which these puzzles would normally be stated. So you might imagine that the puzzles give you reason to modus tollens and reject that premise, ending up with nihilism (that's how Unger's original presentation of the POM went, if I recall). But that's no good if we can state equally compelling puzzles in the nihilist's preferred vocabulary.
Take our maximality scenario. Nihilists allow that we have, not a rock, but some things arranged rockwise. And we now conceive of a situation where those things, arranged just as they actually are, still exist (let "Rocky" be a plural term that picks them out). But in this situation, they are surrounded by more things of a qualitatively similar arrangement. Now are the things in Rocky arranged rockwise? Don't consult intuitions at this point---"rockwise" is a term of art. The theoretical role of "rockwise" is to explain how ordinary talk is ok. If some things are in fact arranged rockwise, then ordinary talk should count them as forming a rock. So, for example, van Inwagen's paraphrase of "that's is a rock" would be "those things are arranged rockwise". If we point to Rocky and say "that's a rock", intuitively we speak falsely (that underpins the original puzzle). But if the things that are Rocky are in fact arranged rockwise, then this would be paraphrased to something true. What we get is that "are arranged rockwise" expresses a maximal, extrinsic plural property. For a contrast case, consider "is a circle". What replaces this by nihilist lights are plural predicates like "being arranged circularly". But this seems to express a non-maximal, intrinsic plural property. I can't see any very philosophically significant difference between the puzzle as transcribed into the nihilists favoured setting and the original.
Similarly, consider a bunch of (what we hitherto thought were) cloud-candidates. The nihilist says that none of these exist. Still, there are things which are arranged candidate-cloudwise. Call them the As. And there are other things---differing from the first lot---which are also arranged candidate-cloudwise. Call them the Bs. Are the A's or the B's arranged cloudwise? Are there some other objects, including many but not all of the As and the B's that *are* arranged cloudwise? Again, the puzzle translates straight through: originally we had to talk about the relation between the many cloud-candidates and the single cloud; now we talk about the many pluralities which are arranged candidate-cloudwise, and how they relate to the plurality that is cloudwise arranged. The puzzle is harder to write down. But so far as I can see, it's still there.
Pursuing the idea for a bit, suppose we decided to say that there were many distinct pluralities that are arranged cloudwise. Then "there at least two distinct clouds" would be paraphrased to a truth (that there are some xx and some yy, such that not all the xx are among the yy and vice versa, such that the xx are arranged cloudwise and the yy are arranged cloudwise). But of course it's the unassertibility of this sort of sentence (staring at what looks to be a single fluffy body in the sky) that leads many to reject Lewis's "many but almost one" response to the problem of the many.
I don't think that nihilism leaves everything dialectically unchanged. It's not so clear how many of the solutions people propose to the problem of the many can be translated into the nihilist's setting. And more positively, some options may seem more attractive once one is a nihilist than they did taken cold. Example: once you're going in for a mismatch between common sense ontology and what there really is, then maybe you're more prepared for the sort of linguistic-trick reconstructions of common sense that Lewis suggests in support of his "many but almost one". Going back to the case we considered above, let's suppose you think that there are many extensionally distinct pluralities that are all arranged cloudwise. Then perhaps "there are two distinct clouds" should be paraphrased, not as suggested above, but as:
there are some xx and some yy, such that almost all the xx are among the yy and vice versa, such that the xx are arranged cloudwise and the yy are arranged cloudwise.
The thought here is that, given one is already buying into unobvious paraphrase to capture the real content of what's said, maybe the costs of putting in a few extra tweaks into that paraphrase are minimal.
Caveats: notice that this isn't to say that nihilism solves your problems, it's to say that nihilism may make it easier to accept a response that was already on the table (Lewis's "many but almost one" idea). And even this is sensitive to the details of how nihilism want to relate ordinary thought and talk to metaphysics: van Inwagen's paraphrase strategy is one such proposal, and meshes quite neatly with the Lewis idea, but it's not clear that alternatives (such as Dorr's counterfactual version) have the same benefits. So it's not the metaphysical component of nihilism that's doing the work in helping accommodate the problem of the many: it's whatever machinery the nihilist uses to justify ordinary thought and talk.
There's one style of nihilist who might stand their ground. Call nihilists friendly if they attempt to say what's good about ordinary thought and talk (making use of things like "rockwise", or counterfactual paraphrases, or whatever). I'm suggesting that friendly nihilists face transcribed versions of the puzzles that everyone faces. Nihilists might though be unfriendly: prepared to say that ordinary thought and talk is largely false, but not to reconstruct some subsidiary norm which ordinary thought and talk meets. Friendly nihilism is an interesting position, I think. Unfriendly nihilism is pushing the nuclear button on all attempts to sort out paradoxes statable in ordinary language. But they have at least this virtue: the puzzles they react against don't come back to bite them.