Yes, you can nominate anyone, as long as they agree to being nominated. More than one nomination would be fine - I think it's probably best to have a maximum though, so maybe we could say that one person can only nominate a maximum of 4 others?
Thanks for putting your name forward Gower. At the moment you're the only one so you're in the running for both Head Boy and Head Girl.
Quick - someone put their name forward or nominate someone for Head Girl and save Gower from having to be both!