It IS Mia who is better! Not only her music has influence the world but even she as a person! She has won a lot of awards and prizes for her work and "is the only artist in HISTORY to be nominated for an Academy Award, Grammy Award, Brit Award, Mercury Prize and Alternative Turner Prize, and the first artist of Asian descent to be nominated for an Academy and Grammy Award in the same year." Mia is named of one of the world's most inluental people,by Time Magazine,Esquire Magazine etc.
That's why M.I.A knocks Nicki Minaj out!!
Wikipedia and tv :)