Contact the NACA Member Assistance Program at 281-968-6222 and explain your situation. You will likely have to provide evidence to support your reasons, but it shouldn’t be too difficult to get a waiver.
Your bigger concern will likely be if you received money from any sort of down payment assistance program when buying the home. Their five year occupancy requirements are usually much stricter.
The lien was explained in your initial Home Buyer’s Workshop and is also detailed in your Workbook. NACA places a $25,000 lien on the property to enforce the owner occupancy requirement of the NACA loan, and it remains in place as long as you have the NACA mortgage. The lien has no effect whatsoever on your credit score.