Ofcourse you can nest grids aswell.
<div class="row">
<div class="tiny-12 medium-6 large-8">
<div class="example-box">
<div class="row">
<div class="tiny-12 medium-6 large-6">
<div class="example-box-nested"></div>
</div>
<div class="tiny-12 medium-6 large-6">
<div class="example-box-nested "></div>
</div>
</div>
</div>
</div>
<div class="tiny-12 medium-6 large-4">
<div class="example-box"></div>
</div>
</div>