Combine chocolate crumbs & butter in a medium bowl. Press onto the bottom & 1-inch up the sides of the prepared springform pan. Bake for 10 minutes. Remove from oven.

Beat cream cheese & sweetened condensed milk in a large mixer bowl until smooth. Add sugar, eggs, lime juice, & vanilla extract; beat until combined.

Microwave 1½ cups morsels in a medium, uncovered microwave-safe bowl on HIGH (100% power) for 1 minute; STIR. The morsels may retain some of their shape. If necessary, microwave an additional 10- to 15-second intervals, stirring just until morsels are melted.

Stir 2 cups of cheesecake batter into melted morsels; mix well (this will be REALLY thick.) Alternately spoon batters into crust beginning & ending with yellow batter.

Place foil wrapped springform pan in the center of a large-rimmed baking sheet. Place into oven. Fill the baking sheet full of water, surrounding the cheesecake. Close oven & bake for 70 to 75 minutes or until the edge is set. Keep the door closed. Turn off the oven & allow to rest for 2-3 hours with the oven door still closed.

Remove cheesecake from oven & allow to finish cooling at room temperature. Once cool, run a warm knife around the edge of the cheesecake. Drizzle chocolate & caramel syrups over the top & sprinkle with mini morsels (& nuts if desired.)

Refrigerate several hours or overnight. Remove sides of pan, slice using a hot knife, running the knife under hot water in-between passes.