@asitamin , in such a case, you are a resident of the USA from the day you were admitted with the GreenCard by the USIS and thus you need / needed to file your US return on form 1040 (NOT 1040-NR). You are therefore also subject to FBAR and FATCA regulations -- just note however while FBAR threshold remains at US$10,000 the FATCA ( form 8938 ) is based on your filing status and tax-home ( domestic or foreign). Also because you have a foreign tax home , you can avail yourself of "foreign earned income' exclusion eligibility and/or foreign tax credit ( for taxes paid to Canadian tax authorities) -- you will obviously have to "resource" your remote earnings to Canada ( where the work is done) -- you may indeed have no US sourced income.
It is not hard to do this , but it may be easier ( at least for the first year ) to have a tax professional ( whom is familiar with international taxation) do this for you. There must be tons of such people in Canada -- lots of Canadians must be working remotely for US entities.
Is there more I can do for you ?
pk
