SNAP Abuse and Fraud Prevention Act of 2018 This bill amends the Food and Nutrition Act of 2008 to require the Department of Agriculture (USDA) to implement the National Accuracy Clearinghouse (NAC) on a nationwide basis. (The NAC is currently a five-state pilot program.) The NAC is a database of Supplemental Nutrition Assistance Program (SNAP, formerly known as the food stamp program) information for states to use to prevent SNAP participants from receiving duplicative benefits in multiple states. The bill requires all states to use the NAC when making SNAP eligibility determinations and specifies requirements for USDA regulations implementing this bill.