Answer:
Yes. There is an agreement error between 'anyone' (a singular pronoun) and 'their' (a plural pronoun).
Explanation:
Some ways to fix the error ....
After anyone eats Yzma's famous chili, he or she swears to never try another kind.
OR
After people eat Yzma's famous chili, they swear to never try another kind.
By the way, there is another error in the sentence !!!!!!
NO: 'to never try'
YES: 'never to try'
