Line a 9-in. square baking pan with foil and grease the foil. In a small bowl, combine the graham cracker crumbs, pecans and butter. Press into prepared pan; set aside.
In a large mixing bowl, beat the cream cheese, sugar and sour cream until smooth. Add eggs; beat on low speed just until combined. Stir in vanilla. Pour over crust.
Bake at 325° for 35-40 minutes or until center is almost set. Cool on a wire rack. Refrigerate until chilled. Freeze overnight.
In a microwave-safe bowl, melt chocolate and shortening, stirring occasionally until smooth. Cool slightly. Using foil, lift cheesecake out of pan. Gently peel off foil; cut into 49 squares. Remove a few pieces at a time for dipping; keep remaining squares refrigerated until ready to dip.
Using a toothpick, completely dip squares, one at a time, in melted chocolate. Place on waxed paper-lined baking sheets; spoon about 1 teaspoon chocolate over each. (Reheat chocolate if needed to finish dipping.) Let stand for 20 minutes or until set. Store in an airtight container in the refrigerator or freezer