Colin here, creator of Nub. I’ve had the general shape of this in mind for years. Nub runs your code with stock `node`, augmented with a `--require` preload hook[0] that adds a transpiler (oxc-powered, packaged as a Node-API add-on), registers a module resolution hook[1], and injects polyfills as needed for APIs like `Worker`, `Temporal`, etc. All purely additive, your code ultimately runs using Node’s actual engine & stdlib implementations.
Cloudflare Workers is a different runtime and has its own toolchain around it. Nub could theoretically support it when executing files (spawn `wrangler dev` instead of `node` if wrangler.toml is detected or something) but really I'm focused on making the Node.js experience as good as possible.
The other pieces of the toolkit could absolutely be used: package manager, script runner, package runner. Works with anything that implements the Node module resolution algorithm (actually Yarn PnP also works out of the box...).