[b]1:[/b] You should consider that she's just a highschool girl. Girls her age are usually ridiculously weak to begin with, so without a power boost she would be losing to most boys her age and virtually everybody older than her.
[b]2:[/b] She's a highschool girl, her Victor's boost is based entirely on the awesomeness of her victory. Winning a game of ping pong or a small local track and field competition would give her only a minuscule boost...
[b]3:[/b] "She's on her way to becoming a demigod."
...Yeah, which is totally unlike forming a contract of power with a supernatural being. /logic

[i]Bonus Round: Nike's power only declares a winner, they have to actually win first...[/i]