Line 8x4-inch loaf pan with foil, leaving edges of foil hanging over sides of pan. In blender, empty contents of smoothie pouch. Add sweetened condensed milk. Cover; blend on high speed 1 to 1 1/2 minutes, stopping blender to scrape down sides as necessary, until smooth.
Pour into large bowl. Fold in whipped topping until blended. Gently fold in meringue cookie pieces. Pour mixture into foil-lined loaf pan. Meringue pieces will float to top of mixture. Freeze at least 8 hours until firm.
To serve, use foil to lift frozen loaf from pan. Pull back foil. Cut into eight 1-inch slices. Serve immediately. Serve with fresh berries and mint, if desired.