I believe it's because generally nice guys are too soft and don't show any masculine traits or don't have any toughness. They don't look like man on the eyes of women.
But if a man, manly and confident enough and also good person i don't see any reason women wouldn't choose that man over bad boy, evil type of man.
Look at people like Chris Hemsworth they are strong, masculine guys but also good, nice guys.
What do you think?