I was a student on a visa in the US and was also working at the university from 2012 to Nov 2019. I then moved out of the US at the end of Nov 2019. Officially, I'm still a student at my US university until May 2020 when I get my degree, but I'm no longer paying tuition or getting paid for my job. I noticed I received the stimulus check of $1200 in my US bank account that I hadn't closed. Am I really eligible for this even though I'm not in US? I'll be filing 2019 taxes though.
The IRS used 2019 tax-filing information where available (otherwise 2018) to determine eligibility for stimulus checks. Since you were a legal resident of the U.S. in 2019 and filed your taxes as such, you were deemed eligible. The way the law is written, the checks are basically an advance on a 2020 tax credit; however, if you would otherwise be deemed ineligible based on your 2020 tax/residency status, you do not have to pay back what you received. You are not required to file taxes if you wouldn't otherwise, and if you do file U.S. taxes, the amount you received will not be clawed back. So the money is yours!