If you are applying for an Chevening Award from an ODA-eligible country, you must be resident in an ODA-eligible country. This does not have to be the country of citizenship.

For example, you could apply for a Chevening Scholarship as an Egyptian citizen while living in Brazil (an ODA-eligible country), but you would be expected to go back to Egypt at the end of your award.

You could not apply for a Chevening Scholarship as an Egyptian citizen while living in the USA because the USA is not an ODA-eligible country.