You will find the delete option link in the Privacy Choices in Twitch, not the settings.
How to delete your Twitch account
Here’s how to delete your Twitch account permanently.
- 1) Find the appropriate link in the Privacy Choices in Twitch (NOT IN THE SETTINGS)
- 2) Click on the link to delete the Twitch account.
- 3) Log into your account.
- 4) Click on “Delete Account”.
- 5) Click 'Delete' on the dialogue box.
Delete Twitch account
Your Twitch account will be completely disabled for 90 days.