Therefore, there isn't a single font that you can definitively say is "the" Georgia Nicolson font.
However, if you are looking for fonts that are commonly used for teen fiction and might be a good fit for the style of the books, you could try:
* Fonts with a playful, energetic feel: Comic Sans MS, Chalkboard, KG Happy, or similar fonts.
* Fonts with a modern, approachable feel: Arial, Helvetica, or Verdana.
You can explore different fonts online using websites like Google Fonts, Dafont, or Font Squirrel to see what works best for you.