Stop Child Hunger Act of 2023 This bill expands the Department of Agriculture's (USDA's) Summer Electronic Benefit Transfer Program for Children (Summer EBT) to include coverage during a school closure period. (Summer EBT provides grocery-buying benefits to low-income families with school-aged children when schools are closed for the summer.) Under the bill, a school closure period means a period in which an elementary school or secondary school is closed, operating remotely, or operating in a hybrid manner for five or more consecutive weekdays during a calendar year. The bill also increases the daily value of the benefit to cover the cost of breakfast, lunch, and a snack for every day school is closed. USDA must pay each state agency and covered tribal organization 100% of the administrative expenses (currently 50%) incurred in operating the program. USDA must also provide grants to states to support the development or upgrading of data systems that are necessary to implement Summer EBT.