JSFiddle - React, Tailwind, and code Playground

HTML

<div class="chat">
  <div class="chat__message">1</div>
  <div class="chat__message">2</div>
  <div class="chat__message">3</div>
  <div class="chat__message">4</div>
  <div class="chat__message">5</div>
  <div class="chat__message">6</div>
  <div class="chat__message">7</div>
  <div class="chat__message">8</div>
  <div class="chat__message">9</div>
  <div class="chat__message">10</div>
</div>

CSS

.chat {
  display: flex;
  flex-direction: column-reverse;
  height: 200px;
  overflow: scroll;
}
.chat__message {
  padding: 5px 10px;
  border: 1px solid gray;
}