Preheat the oven to 350°F and lightly spray a 9x13-inch pan.
Mix crushed Teddy Grahams and melted butter until sandy, press evenly into the pan, bake 10 minutes, and cool slightly.
Beat cream cheese and sugar smooth; add pumpkin, cinnamon, pumpkin pie spice, and nutmeg until combined.
Beat in eggs one at a time, spread over the crust, and bake 30 to 35 minutes until edges set and the center is softly jiggly.
Cool the cheesecake layer on a rack for 1 hour.
Whisk pudding mixes and half-and-half until thickening; stand a few minutes and stir in 1 cup Cool Whip.
Spread pudding over the cooled cheesecake, then spread remaining Cool Whip on top.
Cover and refrigerate at least 6 hours or overnight; add pecans, cut into squares, and serve chilled.