In a medium mixing bowl using a hand mixer whip together the sweetened condensed milk, cream cheese and pudding mix. Beat for 2 minutes until the cream cheese has completely incorporated. Whip in 1/2 of the whipped topping.
Spread the filling into the graham cracker crust. Top with the remaining whipped topping. Sprinkle with ground cinnamon.
Chill for at least 4 hours or overnight before cutting.
Notes
If you can't find the instant pumpkin spice pudding mix this is how you can adapt this pumpkin pie:
Whip together cream cheese with one 1 cup of pureed canned pumpkin, one 3.4 ounce box cheesecake flavored instant pudding and sweetened condensed milk. Add 1 cup of powdered sugar and 1-2 tsp pumpkin pie spice to the mixture. Whip until fully combined and smooth.
Taste and add additional pumpkin pie spice to your taste.
Fold in whipped topping per the recipe and spread into pie shell.