Chrome Apps are more like sandoxed Electron apps which do not require the user to install the same runtime every time for each app installed, unlike Electron. No need for NaCL, they can be written in Javascript.

Not NACL. JavaScript/HTML/CSS. But with access to local filesystems, sockets, etc.

Because of that, Google's suggested replacement of Android Apps (won't work everywhere Chrome does) or PWAs/Extensions (both heavily sandboxed) doesn't work.

no not at all.

There are javascript+html+css apps that could use the Chrome API ( https://developer.chrome.com/apps/api_index ) which allow them to do more than regular javascript+html+css web pages.

There is no compilation.

> I.i.r.c. Chrome Apps are compiled binaries specific for Chrome (NaCL),

NaCl was supported in Chrome Apps, but most Chrome Apps are just web apps using the chrome.* APIs, not NaCl.