Absolutely! The process might be a little different depending on the host you want to boot from.
For Linux, you need to set up DHCP and TFTP properly. Our SDK Setup script helps with this quite a bit. Depending on what DHCP Server you choose to use, you might have to restart it when the USB interface is recognized in order to get it looking at the new connection.
For Windows, I would use our Uniflash tool documented here:
https://processors.wiki.ti.com/index.php/Sitara_Uniflash_Quick_Start_Guide
In either case, you need a SPL/u-boot combo set up to boot from the appropriate interface. Again, the SDK provides some default configs that should help with this quite a bit.
I've successfully booted and mounted a rootfs over NFS all over USB on a Beaglebone Black (from both Linux and Windows).
Let us know if you have further questions.