While I don't know too much about nursing, I do know that Canadian medical schools don't discriminate against what university you completed your degree in or your degree, but take note that you should have all of your necessary prerequisite courses. Also take what you read from internet forums with a grain of salt, if you would like learning more about what the Canadian medical school are looking for I recommend looking up the medical school websites or flip through the AFMC doc with updated admissions info.
From the 2019 Mac med stats (http://mdprogram.mcmaster.ca/docs/default-source/admissions/classof2019.pdf?sfvrsn=2) it notes that about 3 students with a Bachelors of Nursing were accepted. So students with nursing degrees do get accepted into medical school, but not as many as people with science or health science degrees likely since less nursing students apply.
Ultimately, it's up to you to decide on what undergraduate degree to study for four years so it should definitely be one that you enjoy!