Nested grid possible or nav on the side?

[Kugeleis]

I'd like to have the nav on the side and tried to do this as a nested grid like so

<div class="grid">
        <div class="left">
            <nav>my nav to the right</nav>
        </div>
        <div class="right">
            <div class="grid">
                <article>Foo</article>
                <article>Bar</article>
            </div>
        </div>
 </div>

but this doesn't work. Is there a way with PicoCSS to have a right nav or do I need to add own css?