Preheat oven to 375°F.
In a bowl, cream butter and brown sugar until fluffy.
Add flour, oats, and nuts. Mix well.
Press dough into a greased 12-inch circle on a pizza pan, forming a rim.
Prick with a fork and bake for 10–12 minutes or until golden. Cool completely.
In a separate bowl, combine sweetened condensed milk, sour cream, lemon juice, and vanilla. Mix until smooth. Chill.
Arrange bananas over cooled crust.
Spread filling evenly over bananas.
Top with pineapple, cherries, and nuts.
Melt chocolate and drizzle over the top.
Chill before serving.