Hello. I just got pokemon essentials and i was wondering if scaling levels based on gym badges is possible. Like if you have 1 badge the guy has a Lvl 15 Rattata, but if have none he has a level 5. Is there a script that can do this?

You would need to check for badges in the Event:

Conditional Branch: Defeated Gym 1 == On
(battle with level 15 Rattata here)
else
(battle with level 5 Rattata here)
end

You aren't just limited to checking for 1 gym, you can create an event that has different battles based of if the player has all the badges if you wanted to.