{% load url from future %}
<{{ tag }} class="{% if user.is_authenticated %}edit_chunk{% endif %}" data-key="{{ chunk_key }}">
    {{ obj.content|safe }}
    {% if request.user.is_authenticated %}
    <a href="{% url 'admin:chunks_chunk_change' obj.pk %}">редактировать</a>
    {% endif %}
</{{ tag }}>