In a small saucepan, combine caramels and evaporated milk. Cook and stir over medium-low heat until smooth; stir in 1/2 cup pecans. Pour into crust. Refrigerate for 15 minutes.
Meanwhile, in a large bowl, beat cream cheese and sour cream until smooth. In a small bowl, whisk milk and pudding mix for 2 minutes; beat into cream cheese mixture until blended. Spread over caramel mixture. Refrigerate for at least 30 minutes. Before serving, drizzle with hot fudge topping and sprinkle with remaining pecans.