You'd need an add-on to automatically do it, not sure if one exists.
You can do a basic HTML widget though:
	
	
	
		Code:
	
	
		<ol class="categoryList is-active">
    <li class="categoryList-item">
        <div class="categoryList-itemRow">
            <a href="CATEGORYLINKHERE" class="categoryList-link">
                Category 1
            </a>
        </div>
        <ol class="categoryList is-active" tabindex="-1" style="">
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #1
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #2
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #3
                    </a>
            </li>
        </ol>
    </li>
</ol>
<ol class="categoryList is-active">
    <li class="categoryList-item">
        <div class="categoryList-itemRow">
            <a href="CATEGORYLINKHERE" class="categoryList-link">
                Category 2
            </a>
        </div>
        <ol class="categoryList is-active" tabindex="-1" style="">
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #1
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #2
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #3
                    </a>
            </li>
        </ol>
    </li>
</ol>
	 
 
Result was:
View attachment 190033
or:
	
	
	
		Code:
	
	
		<ol class="categoryList toggleTarget is-active">
    <li class="categoryList-item">
        <div class="categoryList-itemRow">
            <a class="categoryList-toggler" data-xf-click="toggle" data-target="< :up :next" role="button" tabindex="0" aria-label="Toggle expanded"></a>
            <a href="CATEGORYLINKHERE" class="categoryList-link">
                Category 1
            </a>
        </div>
        <ol class="categoryList toggleTarget" tabindex="-1" style="">
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #1
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #2
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #3
                    </a>
            </li>
        </ol>
    </li>
</ol>
<ol class="categoryList toggleTarget is-active">
    <li class="categoryList-item">
        <div class="categoryList-itemRow">
            <a class="categoryList-toggler" data-xf-click="toggle" data-target="< :up :next" role="button" tabindex="0" aria-label="Toggle expanded"></a>
            <a href="CATEGORYLINKHERE" class="categoryList-link">
                Category 2
            </a>
        </div>
        <ol class="categoryList toggleTarget" tabindex="-1" style="">
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #1
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #2
                    </a>
                </div>
            </li>
            <li class="categoryList-item">
                <div class="categoryList-itemRow">
                    <a href="NODELINKHERE" class="categoryList-link">
                        Node #3
                    </a>
            </li>
        </ol>
    </li>
</ol>
	 
 
View attachment 190034