If a Teacher or Administrator is creating a new class and the "Pearson products or courses" option is not enabled (as shown below), there can be two root causes.  

For the user impacted, ensure that within their profile they have the NovaNET Courseware program association.  If that is in place and you still cannot see the Pearson courses, then the NovaNET Courseware license is likely expired.  Please contact Pearson Customer Service at 888.827.0772 to ensure that your license is still active and work with them to resolve.