Jody Lukoki opened the scoring in the 13th minute after Lasse Schone intercepted a pass in midfield. Christian Eriksen and Tobias Sana then made it 3-0 with only 20 minutes gone.
A blunder by Nijmegen goalkeeper Gabor Babos gifted Theo Janssen (pictured) a fourth for the visitors after 37 minutes, with Siem De Jong and Sana adding two more after the break.
Bram Nuytinck had scored a consolation for the hosts after the hour to pull it back to 5-1.
United States striker Jozy Altidore scored twice as AZ Alkmaar enjoyed a 3-1 home win against Heracles Almelo, while ADO Den Haag needed a late Danny Holla goal to salvage a point in a 2-2 draw against 10-man RKC Waalwijk.
Waalwijk twice went ahead through Teddy Chevalier, who scored his second in the 89th with his side down to 10 men after Sigourney Bandjar's dismissal midway through the second half.
Groningen and promoted Willem II Tilburg also shared the points in a 1-1 draw.
Twente Enschede won 1-0 at NAC Breda on Saturday and top the table with a maximum of six points, two clear of a chasing pack of five clubs led by Ajax.
