Preheat oven to 400 degrees. Lightly grease a large, rimmed sheet pan with oil or line with parchment or foil for easy clean up.
In a large bowl mix ground chicken, chopped spinach, grated parmesan, 2 tablespoon of marinara sauce, 1/2 tsp garlic powder, 1/4 tsp salt, Italian seasoning, egg, and breadcrumbs.
On the sheet pan, form the chicken mixture into 4 equal, oval shaped mini meatloaves, like you are making a big meatball but with a flat top. Spoon the remaining marinara on the top of each of the meatloaves then sprinkle with the shredded mozzarella.
Toss the broccoli florets with a tablespoon of oil, a 1/4 tsp of salt, and a 1/4 tsp of garlic powder. Scatter the broccoli on the pan around the meatloaves.
Bake until the cheese is browned and bubbly and the meatloaves are cooked through, 15 to 20 minutes. (The internal temp should be 165 or you can cut one open to make sure it is no longer pink inside.) Serve with broccoli and cooked pasta, if desired.