Flat is an excellent music notation editor that works directly with GSuite. You install it from the Chrome store into your Chrome account and you will have a sheet music editor that allows for collaborative editing and creation.
Noteflight is a robust application for music teachers. They do offer a free trial, but in order to access this, you must contact the company. Their product prices in at approximately $7 per student, and membership allows the teacher to organize classes, create assignment and gives access to a library of musical scores and lessons. Their site specifically states that their application works on Chromebooks.