I absolutely love unlocking my MacBook Pro with my fingers. I could live without it, of course, but it's really convenient!
The good news is that it's natively available as a PAM module! Meaning Touch ID can be used to authenticate with sudo.
All you need to do is to add this line to
# sudo: auth account password session auth sufficient pam_tid.so #<= this line auth sufficient pam_smartcard.so auth required pam_opendirectory.so account required pam_permit.so password required pam_deny.so session required pam_permit.so
It will make Touch ID the default authentication method but will fallback to others if needed.
If you're using iTerm2, there is a bug on recent version so you need to turn off Preferences > Advanced > Allow sessions to survive logging out and back in.
That's it 🎉