map values from checkbox field into category field using SQL
FeedMe plugin imports categories, so you could create an xml template file that outputs your entries and their checkbox values(separated by commas), then use FeedMe to import that file back in and map those checkboxes to your categories. They just have to match spelling, otherwise FeedMe will create a new category

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Something like:

&lt;xml&gt;
  &lt;blog&gt;
    {% for entry in entries %}
      &lt;entry&gt;
        &lt;title&gt;{{ entry.title }}&lt;/title&gt;{# required for import #}
        &lt;category&gt;&lt;![CDATA[{% for option in entry.checkboxFieldHandle %}{{ option }}, {% endfor %}]]&gt;&lt;/category&gt;
      &lt;/entry&gt;
    {% endfor %}
  &lt;/blog&gt;
 &lt;/xml&gt;