Heat oven to 375°F. Spray 8-inch square (2-quart) glass baking dish with nonstick cooking spray. In large saucepan, combine cheese product and milk; cook over low heat until cheese is melted, stirring occasionally.
Add hash-brown potatoes and mixed vegetables; mix well. Spoon mixture into sprayed baking dish. Arrange fish sticks over top.
Bake at 375°F. for 25 to 35 minutes or until casserole is thoroughly heated and bubbly around edges.