Country of residence/nationality/citizenship
Your country of residence is the country in which you are currently living in, at the time you process your verification request. You do not need to have citizenship to your country of residence nor do you need to have been living in this country for a certain period of time; essentially your country of residence will be the country in which you use a residential mailing address. Your country of residence will also imply your intention to live in this country for the foreseeable future.
Your nationality, on the other hand, is the country in which you have citizenship and will be stated in your passport.