For the cupcakes: Preheat the oven to 175°C. Line two 12-cup standard muffin tins with cupcake liners. Whisk together the flour, baking powder, baking soda and salt in a small bowl. Set aside.
Combine the butter, granulated sugar, sour cream, vanilla and eggs in a large bowl and whisk until smooth. Stir in the flour mixture until just combined. Stir in the chocolate chips. Divide the batter evenly among the muffin cups, filling each about three-quarters full. Bake until a toothpick inserted in the center of a cupcake comes out clean, 21 to 23 minutes, rotating the pans once about halfway through baking. Cool the cupcakes in the pans for 5 minutes, and then transfer to a wire rack to cool completely.
For the frosting: Beat the butter, peanut butter, vanilla and salt using an electric mixer on medium speed until smooth and fluffy, about 2 minutes. Gradually beat in the confectioners' sugar and continue to beat until smooth and fluffy, about 2 minutes more.
For the assembly and decorating: Put 1 cup of frosting in a piping bag fitted with a large round tip and set aside. Put the jimmies in a shallow bowl. Frost a cupcake, using about 2 tablespoons of the remaining frosting per cupcake, and then gently dipping the top into the jimmies, turning the cupcake until the top is coated. Repeat with the remaining cupcakes. Arrange the cupcakes in 4 rows on a large serving plate or cutting board. Fit a marshmallow between each cupcake, 5 marshmallows per row, to fill in the gaps between the cupcakes in the rows. Using the frosting in the piping bag, pipe thick cross shapes between where the cupcakes meet one another and over the marshmallows so there are no visible gaps between the cupcakes. Sprinkle with jimmies to coat.
To make goal posts for the cupcake "field," microwave the chocolate chips in a small microwave-safe bowl until just melted, 30 to 45 seconds. Keep 2 cookie sticks whole for the bases of the posts. Cut off and discard (or eat!) the bottom third of the remaining cookie sticks. Dip the top of one of the longest cookie sticks into the melted chocolate and adhere it to the middle of one of the cut cookie sticks so that they form a capital T shape. Next, dip the cut ends of two short sticks into chocolate and adhere them to either side of the cross on the T. Lay the goal post on a flat surface and repeat with the remaining 4 cookie sticks to make the second goal. Allow goals to fully harden, 15 to 20 minutes, or place in the refrigerator for 10 minutes.
Using the decorators' icing, pipe 10 lines across the cupcake field to represent yard lines. Pipe out the number 50 in the middle for the 50-yard line. Heat the Tootsie Rolls in the microwave on high in 5-second intervals until they are soft and pliable. Mash them together and form into a football. Use the icing to pipe the lacing on the football; use a toothpick if necessary to help define the lacing. Place the football on the field. Place the gummy candies on the field to represent players and then stick the goal posts into cupcakes at each end of the field.