Preheat your oven to 350°F.
Slice the croissants in half horizontally and place them on a baking sheet.
In a mixing bowl, combine the shredded chicken, romaine lettuce, Caesar dressing, grated Parmesan cheese, black pepper, and garlic powder. Mix well until everything is evenly coated.
Spoon the chicken mixture generously onto the bottom half of each croissant.
Place the top half of the croissant over the filling.
Bake in the preheated oven for about 10 minutes, or until the croissants are warm and slightly toasted.
Remove from the oven and, if desired, sprinkle extra Parmesan cheese on top before serving.