Place 4 large pieces of aluminum foil on the counter or table. Place 1 flour tortilla on each piece of foil. Scoop chocolate chips and marshmallows into the center of each tortilla. Roll each tortilla like a burrito, capturing all ingredients inside the tortilla. Completely cover the rolled S'morito with aluminum foil. Using long-handled tongs, carefully place each S'morito on the grill or on the campfire coals. Cook for 3 to 5 minutes, depending on the heat intensity of the fire, turning often to ensure even cooking. The S'moritos are done when all ingredients have melted together.