Preheat oven to 350 degrees F. Spray a 12-cavity muffin tin with cooking spray liberally. Set aside.
Unroll the refrigerated pie crusts and, using a 3" cookie cutter, cut circles from the dough. Gently stretch the dough a little, then push down and up the sides in each muffin cup. Repeat with remaining muffin cups.
Meanwhile, in a large bowl, whisk together the corn syrup, sugar, egg, butter and vanilla until combined. Stir in the chopped pecans and chocolate chips until combined.
Portion Tablespoons of the filling among each pie crust, careful not to over-fill. You may have extra filling, so make more pies with another pie tin. Top each filled cup with a pecan half.
Bake for approx. 25-30 minutes or until pies are bubbly and crust is golden brown. Cool for about 5 minutes in the pan, then gently remove with a knife or spoon and place on a wire rack to cool completely.