You can add a main heading to your table with:

nltHeading 'Heading Text'  © or
nltSet 'head' 'My Heading'

The heading only appears on the first page of the table, if it spans several pages either horizontally or vertically. By default, the heading is centred, but this may be changed using the heading style. You may also change the font and colour of the heading. You can specify linebreaks in the heading by including the semi-colon character in the heading text or by passing a nested vector:

nltHeading 'This is Line-1;This is the Second line' 
nltHeading 'Here is' 'my Heading'

See also table caption, subhead and footnote for other ways of adding text elements to tables.