This morning I updated from Prismic 0.1.0-beta.1 to the latest 1.0.0 update. It looks like the function getStories, used in the Nuxt config file was causing storybook to break because it was looking for the stories in the wrong path, it was looking in .nuxt-storybook/assets instead of .slicemachine/assets.
For a temporary fix I updated my Nuxt config and hardcoded the correct path.
Alright, I found some time to run your project. What happens is that Nuxt-Storybook takes relative paths as-is, so the paths inside nuxt.config are wrong by default. For the moment, you can prefix them with ~/.