Heat oven to 375 degrees.
Spray muffin tins with vegetable spray.
in a medium mixing bowl, stir together squash, egg, mozzarella, Italian herbs and salt.
Divide squash mixture evenly among muffin cups. Press down the center of each with back of spoon.
Bake nests for 12 minutes.
While nests are in the oven, gather the rest of the ingredients for assembly.
If the meatballs are from frozen, be certain to warm up in the microwave a bit, to at least room temperature.
Please note: The pan will be hot from the oven when assembling this dish so care must be taken not to touch it or get burned.
Assemble the dish.
add a 1-2 tsp. of marinara to each nest and place a meatball in each one.
Cover meatball with more Marinara and then sprinkle each one with Parmesan.
Return pan to oven for 12 minutes.
Allow nests to cool for 5-8 minutes before removing from pan.
Loosen each nest by going around the edge with a knife.
Gently scoop out nests onto individual plates or party platter.
Serve immediately.