Yes, PCIe is available. If you change carrier boards, then what is available will also change. For the Xavier there is a regular PCIe slot, along with an m.2 key E and key M.
The key M is sandwiched between the dev kit carrier board and module, and would be useful for single sided NVMe, but not for a USB expansion. Some m.2 key E USB expansions would work there. The full-sized PCIe slot would work with most any expansion card if it has the drivers in Linux via the “standard” drivers (some manufacturers may require a custom driver, and many such custom drivers are not available for arm64/aarch64). I think the primary issue for a PCIe slot expansion is making sure you have a stable physical mount (the slot exists, but not the bracket to hold on to the card and prevent movement…any movement at all could cause failures).
Regarding the particular camera, I see this:
Hi-speed USB 2.0 certified
UVC compliant (no software installation required)
Several cameras running on a USB3 HUB will probably not need to worry about bandwidth (you might be able to use a USB3 HUB…preferably external power…and possibly won’t even need more USB ports). Sometimes latency will become an issue even with available bandwidth, but I would tend to believe that odds are this will work.
Regarding drivers, the use of UVC is standard and is already installed on Jetsons, and so the device special file should “just work” upon plugin.
If Logitech produces other software related to this camera, then that software may not work on arm64/aarch64, but I didn’t see any notes of other software. I had to find the camera on an English language web page, so I don’t know what was listed in the URL you posted…maybe it was different than what I saw in the USA.