backdrop-filter not working for nested elements in Chrome

Place the backdrop filter on css pseudo element. This allows nested backdrop filters. Also you can use z-index: -1; to position your backdrop behind your elemets

div {
  height: 100px;
  width: 100px;
}
.wrapper {
  position: absolute;
}
.outer, .inner {
  position: relative;
}
.outer::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}
.outer {
  background: rgba(255, 0, 0, .5);
}
.inner::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  
}
.inner {
  background: rgba(0, 0, 255, .5);
  top: 50px;
  left: 50px;
}
main {
  position: relative;
}

<main>
  <div class="wrapper">
    <div class="outer">
      <div class="inner"></div>
    </div>
  </div>

  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus in id quos, est voluptatibus minus porro sunt totam quod commodi odit maxime similique, dolorum aut quo atque. Deleniti, voluptas animi.</p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus in id quos, est voluptatibus minus porro sunt totam quod commodi odit maxime similique, dolorum aut quo atque. Deleniti, voluptas animi.</p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus in id quos, est voluptatibus minus porro sunt totam quod commodi odit maxime similique, dolorum aut quo atque. Deleniti, voluptas animi.</p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus in id quos, est voluptatibus minus porro sunt totam quod commodi odit maxime similique, dolorum aut quo atque. Deleniti, voluptas animi.</p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus in id quos, est voluptatibus minus porro sunt totam quod commodi odit maxime similique, dolorum aut quo atque. Deleniti, voluptas animi.</p>
</main>

And here is codepen