Make the cake: Preheat oven to 350°F. Line the bottom of one 9-inch cake pan with parchment or waxed paper and spray with nonstick cooking spray.
Whisk the sugar, vanilla, salt, sour cream and egg in a medium bowl. Use a rubber spatula to gently fold the flour, baking powder and baking soda over the wet ingredients. Stir in the butter, chocolate chips and pecans. Do not over mix. Pour the batter in an even layer into the cake pan.
Bake the cake: Place the pan in the center of the oven and bake until a cake tester emerges clean from the center, 20 to 25 minutes. Cool and unmold onto a serving platter.
Ice cream layer: Line the same cake pan with plastic wrap (overlapping) and spoon the ice cream inside. Cover the top with plastic and gently press until it takes the shape of the cake pan. Remove the plastic from on top of the ice cream and place the cake layer on top of the ice cream in the pan so that the bottom of the cake is facing up. Press gently so that the ice cream adheres to the cake. Return the cake to the freezer.
Make the pecan topping: Place the caramels and water in a microwave safe bowl. Microwave on high for 1 minute or until caramels are melted, stirring after 30 seconds. Stir in the ½ cup of pecans to coat with caramel. Spread them out on a baking sheet. Reserve any remaining caramel, warm, in the bowl.
Make the chocolate glaze: Place the chocolate and cream into the top of a double boiler. Heat until the chocolate melts and keep slightly warm.
Serve the cake: Invert the cake onto a serving platter and sprinkle with some of the caramel-coated pecans, drizzle with the caramel, drizzle with the chocolate and top with remaining pecans. Serve immediately or freeze until ready to use.
Put the chocolate into a zip closure plastic bag with one corner cut off to drizzle the chocolate onto the cake.