Checkout Api Using Nodejs

Your issue is that of OAuth scopes. You don’t have permission to create those resources.

Unless you’re a sales channel, you need to use the GraphQL Storefront API to create checkouts, which will ultimately need to be completed on the web interface.

shopify-api-node, while it seems to support GraphQL, only supports the GraphQL Admin API, which does not support checkout creation (again unless you are a sales channel).

Your path forward is likely going to be creating a GraphQL Storefront API client by either forking or contributing to that library, finding an existing one, or creating your own.

Cheers.