it should be supported unless the device cant supply enough power over otg to the drive (you may need to use y cable)
when android mounts it, you can log into the chroot and it should automatically bind mount it somewhere in / (ls /*usb*) but it will probably use a vold overlay so unix permissions might not work on the fs
ls /dev/block/sd* will show you a list of drives that the kernel detects, your otg would most likely be the last one (highest letter), you can try making a /mnt point for it and mounting it there from within the chroot for direct fs access
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