HEAT oven to 375°F. Coat 12-inch pizza pan or baking sheet with no-stick cooking spray. Whisk sweetened condensed milk, sour cream, 1/4 cup lemon juice and vanilla in medium bowl until blended. Cover and chill.

BEAT butter and brown sugar in medium bowl with electric mixer on medium speed until fluffy. Blend in flour and 3/4 cup nuts. Press dough into 12-inch circle on prepared pan, forming rim around edge. Pierce surface with fork. Bake 10 to 12 minutes or until golden brown. Cool completely on wire rack.

ARRANGE 2 sliced bananas on cooled crust. Spoon filling evenly over bananas. Toss remaining sliced banana in 2 tablespoons lemon juice to coat. Arrange banana, pineapple, cherries on top of pizza. Sprinkle with 1/4 cup nuts.

MICROWAVE fudge topping in small heavy-duty resealable plastic bag on HIGH 5 to 10 seconds to warm slightly. Cut very small corner off bag. Drizzle topping over pizza. Chill until ready to serve. Best when served same day.