Nerds are the smartest in the school. They tend to be on the lawful side of things and will always remind the teacher of the homework, even during an apocalypse.
You have disadvantage on any charisma checks.
You start with the following equipment:
(a) Large textbook or (b) Science vials
(a) A poisoner's kit or (b) forgery kit
A backpack with equipment of your choice that fits your class (to be approved by DM).
History
You love learning about the wars and have studied strategy. Because of this you have advantage on any initiative rolls as well as history and survival checks.
Science
There's different sciences but let's be real chem is the coolest. You're able to make potions and poisons and you have advantage on medicine checks.
Geography
You're the map guy. You'll never get lost and you're an expert tracker. You have advantage on perception and survival checks.