I've tried to avoid reading up on the film before watching it, but I did see mentions of this shoe a few times; People suspect a deeper meaning, and have come up with different theories about it.
I do think it's explained away in a line of dialog later, when a character asks something along the lines of 'what's the opposite of a miracle?' It also reminded me of that scene in Us where a frisbee lands in a blanket, perfectly and uncannily matching the towel's colorful circles pattern.
Maybe (probably) I'm just missing something and it does have thematical heft, but my feeling after watching Nope is that the shoe is just a weird, jarring image to induce unease. It later shows up on an uncomfortable scene, but I don't think it's got a coherent theme or message.
All this is a long way of saying I think Nope is mostly free of the deeper meaning that buoyed Get Out and Us; The director has gone on record saying that he wanted to do old school spectacle in the style of movies like Close Encounters or Jaws, and what do you know! Those are the two films I'd most likely compare this against. And while there are plenty of themes in display (the relationship between beasts and their trainers, the search for fame) they don't really cohere into any clear message.
But even if it's not as good as its inspirations or the director's previous films, it's still a huge amount of fun, has great characters and dialogue, and is chock full of beautifully filmed, glorious weirdness. And it's creepy as all hell.
The film's tone is tightly controlled and full of memorable imagery, even if the links between these images aren't as solid as they could be. It starts out a bit slow, but the characters are likeable and funny enough to carry it until the plot kicks into overdrive.
Em and OJ (Keke Palmer and Daniel Kaluuya, both excellent) run the Haywood ranch after their father (the legendary Keith David) is killed by a Fortean rain of coins, keys and other random objects. OJ is the dutiful son, laconic and responsible, trying to keep the ranch going, while Em is the unreliable motormouth pseudo-grifter who considers the ranch her side-gig. Soon they become convinced the ranch is being stalked by a UFO, and are joined by the electronic store employee that installs some high tech cameras for them as they try to get footage of it.
Their neighbor, a former child star (and survivor to the TV set massacre from the prologue) will also be an important part of the story.
To go much further would mean going into spoilers, but after a bit of a slow start it becomes clear that the aliens are definitely not friendly, and the Jaws parallels come to the fore. There are a lot of weird, wonderful scenes, a lot of good suspense and general creepiness. Honestly, some of the images are so bold that they're kind of ridiculous - but that's the best kind of ridiculous!
Both Get Out and Us were heightened by the parallels Peele established to Racism or privilege - I mean, they worked on their own, but the fact that there's a literal and a symbolic level helps shrug off the fact that, well, a goofball secret society worked out how to do consciousness transplants, or the ridiculously fantastical premise behind Us's Tethered. Here there's no such safety net; Sometimes aliens are a parable for immigrants, discrimination or simply the other. And sometimes, they're just sky sharks.