Here's some previous posts and an IRS reference on grants. I do recall seeing (but can't find it) a previous post specific to a grant from a charity and believe the answer was the same: it's taxable.
https://ttlc.intuit.com/community/taxes/discussion/i-received-an-art-grant-from-a-non-profit-and-it-...
https://ttlc.intuit.com/questions/3091932-is-a-fulbright-teaching-grant-to-a-foreign-country-that-pa...
https://www.irs.gov/individuals/international-taxpayers/fulbright-grants
https://ttlc.intuit.com/questions/4695785-have-a-nsf-fellowship-software-is-showing-taxes-of-6000-on...
https://ttlc.intuit.com/community/taxes/discussion/have-a-nsf-fellowship-software-is-showing-taxes-o...
