Preheat the oven to 375ºF (190ºC) and spray a 12-cup muffin pan with cooking spray; set aside.
Unroll the crescent dough, press seams together, and roll or press into an 8×18-inch rectangle; cut into 12 equal squares.
Press each dough square into a prepared muffin cup, forming a cup shape with the dough reaching up the sides.
Place about 1 tablespoon shredded mozzarella into the bottom of each dough-lined cup.
Place one piece of frozen popcorn chicken (or two small pieces) on top of the mozzarella in each cup.
Spoon about 2 tablespoons spaghetti sauce over each chicken piece, then sprinkle each cup with shredded Parmesan (divide remaining mozzarella as desired).
Bake for 15 to 18 minutes, until the dough is golden brown and the chicken is heated through.
Remove from the oven and let cool a few minutes in the pan before transferring to a wire rack to finish cooling slightly; serve warm.