Roll a dice with a modifier from google docs

Is it possible to write an api script to accept a value from a google sheet api call and add it to a dice roll then show that in the chat? I have a very complex rolemaster sheet I would rather not re-create inside roll20. Thanks

Not directly or easily.  The best you could do would be to write a browser extension that would look up information in that google sheet, then issue API commands in the chatbox with the information.

Roll20 is designed to make it difficult, if not impossible, to integrate with any other websites, for security and copyright protection reasons. Somone who knew what they were doing could write a browser extension for this purpose, but otherwise no, it's not possible. If you want to go that route, ou'd be better off finding a comunnity that works with google sheets or browser extensions - it is not the expertise of people here, generally.