Debian on TI-Nspire

I am following this tutorial: https://ivoah.net/blog/2016/03/20/how-to-install-debian-on-a-ti-nspire/ (I have all of the required items.) I am using an Acer Chromebook C720, which I dual-booted Debian buster onto, using crouton. I have a TI-Nspire CX II CAS, which I am trying to dual-boot Debian onto with the help of the tutorial I mentioned. Steps 1 through 5 work fine for me, but when I do

chroot /mnt

in step 6, I get an error:

chroot: failed to run command '/bin/bash': Exec format error

I read here: https://askubuntu.com/questions/14280/during-a-chroot-attempt-i-got-this-error-chroot-failed-to-run-command-bin But I have no idea where to go from there. Should I have dual-booted a 32-bit version of Debian buster, rather than the 64-bit version I am running currently? Any help is greatly appreciated.