Heat grill for indirect grilling: Light one side of grill, leaving other side unlit. Close lid. Heat grill to 300°F.
Spray 12x9-inch disposable foil pan and a sheet of aluminum foil with cooking spray. Stir together all ingredients in pan and cover with foil, sprayed side down.
Place on grill grate on unlit side of grill. Cook for about 30 minutes, stirring every 10 minutes, until thoroughly melted and mixed together.
Serve warm queso dip with tortilla chips, crusty bread, or vegetables.