Nelson struggled in the first half as he missed eight of his 10 shots. But the 5-11 senior came alive after intermission.
Nelson and Delonte West each scored seven points in a 19-5 surge to start the second half, turning a close game into a 48-30 lead for the Hawks with under 16 minutes to play.
West added 18 points and Dwayne Jones had 14 and 11 rebounds for the Hawks (10-0), who matched the 1964-65 team for the best start in school history.
Raphael Madera scored 16 points to lead the Blue Hens (6-3).