How different is Nord UI from other CSS frameworks?

Nord UI targets modern browsers and web apps. it's a tiny framework with easy setup and comes minimum footprint and default styles. so its not meant to be a complete framework with tons of components and styles for building user interfaces, but it will provide you with core components like button, modal, card, form input and so on.
also, we take bundle size seriously and keep package as light as possible. although the minified package bundle is tiny, we exported each component and tool individually to import only what you need.

Is there any recommended setup?

yes, check installtion using package managers. also see import components and assets individually for recommended import method.

Can i use Nord UI in react/angular/vue/svelte/other javascript frameworks?

You can use Nord UI inside any javascript framework. we don't make any assumption about your javascript setup. just import required styles and add CSS classes to your components.

Tree-Shaking support?

You don't have to import the entire package. just import what you need. check import components and assets individually

Do You Support RTL?

Yes. read RTL Guide for details

What is the recommended font?

Use any font that fits into your design. this document is using Lato Font.

Any font icon?

Like typography font, we made no assumption about font icon.

Is Nord UI available on package managers other than NPM and Yarn?

At this moment, only NPM and Yarn package are available and i think that's enough for now.