The student framed their request in terms of using ChatGPT as a grammar checker. The problem is that ChatGPT does much more than simply correct grammar, it selects facts and concepts, drawn from a large collection of work from numerous authors, not always correct, or attributed.
Universities provide advice and assistance with writing. Professor Inger Mewburn at ANU (the Thesis Whisperer), recommends Grammarly, and the free alternative Typely. I used Grammarly as a graduate student, and found it very useful (English is my first, and only, language, but I only barely passed the subject at school).
My experiences in using Chat GPT, and its predecessor GPT3, and other AI, have been mixed. Recently I reviewed a paper generated by Chat GPT. I gave the paper one out of five, and suggested the name of the author should be "Anonymous" with the person who submitted it listed as an editor, not author. But not everyone agreed, with an average review of 2.6 out of 5.
Using an approach similar to a systematic review, the student would set out what they are attempting to accomplish, what queries they tried, what the results they got were, how they selected the most appropriate result, what manual changes they made to the automated result, a critique of the result, and recommendations for improvements to the process. The idea would be the student would demonstrate skill in using a tool to produce a result, and value add to the automated output.