JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr>
        <td>    
            <table border="1">
                <tr>
                    <td>row 1, cell 1</td>
                    <td>row 1, cell 2</td>
                </tr>
                <tr>
                    <td>row 2, cell 1</td>
                    <td>row 2, cell 2</td>
                </tr>
            </table>
        </td>
        <td id="buttonrow">
            <input type="button" value="Button">
        </td>
    </tr>
</table>

CSS

#buttonrow {vertical-align:bottom;}