Prepare Grits: Spray a 9×13″ baking dish with nonstick spray. Bring chicken broth to a boil. Whisk in grits, reduce heat to medium, and cook for 5 minutes, whisking occasionally. Remove from heat and stir in 1-1/2 cups cheese, butter, salt, and pepper until smooth. Pour into dish, cover, and refrigerate until firm (2 hours or overnight).
Cut and Bake: Preheat oven to 400°F. Turn grits out onto a cutting board and cut into 2″ rounds or squares. Place on a parchment-lined baking sheet sprayed with nonstick spray. Bake for 40-45 minutes, flipping halfway, until golden brown.
Cook Topping: With 15 minutes left to bake, cook bacon in a skillet until crispy. Remove bacon, reserving 2 tbsp grease. Sauté shrimp, green onions, and garlic in the grease over medium-high heat for 3-4 minutes until shrimp are pink. Stir in bacon.
Assemble and Broil: Top baked grits with shrimp mixture and sprinkle with remaining cheese. Broil until cheese is melted.
Serve: Serve warm and enjoy!