one piece of advice: go to canada to renew your visa. if you go back to nepal to renew visa and in your I20 they see that you are doing either master's or phd, some consulars might get the impression that you will not come back once you enter US and finish your studies. i know there are tons of cases where people have been issued visa even in nepal for their masters and phds, but don't take any risk in this issue.

not only canada, you can go to any other country to get visa renewed as they don't care if you return to nepal or not; they just see your papers and stamp your pp if you are abiding the law.