Is there a way to watch a sass file in my package.json file without node-sass installed?

I'm trying to watch my sass file upon running my npm start script in my package.json file, is there a good way to do this? I cannot seem to get it to work. I'd also like to have it start my server, which it does do...

"start": "nodemon server/server.js sass --watch mainstyles.scss:style.css"

This is what I'm working with.