Mention nix package in readme (#925)

Readme.md

@@ -65,6 +65,7 @@ The following table lists all available download options:
           <li>🟠 <a href="https://github.com/Tyrrrz/DiscordChatExporter/actions/workflows/main.yml">CI build</a> (<code>DiscordChatExporter.CLI.zip</code>)</li>
           <li>🐋 <a href="https://hub.docker.com/r/tyrrrz/discordchatexporter">Docker</a> (<code>tyrrrz/discordchatexporter</code>)</li>
           <li>📦 <a href="https://aur.archlinux.org/packages/discord-chat-exporter-cli">AUR</a> (<code>discord-chat-exporter-cli</code>)</li>
+          <li>📦 <a href="https://search.nixos.org/packages?query=discordchatexporter-cli">Nix</a> (<code>discordchatexporter-cli</code>)</li>
         </ul>
       </td>
       <td>
@@ -102,4 +103,4 @@ The following table lists all available download options:
 ## Screenshots
 
 ![channel list](.assets/list.png)
-![rendered output](.assets/output.png)
+![rendered output](.assets/output.png)