Preheat the oven to 350°F (175°C) and lightly spray a 9x13-inch baking dish with cooking spray.
Cook the penne pasta according to package directions until al dente, then drain in a colander.
In a large bowl, combine the cooked chopped chicken, minced onion flakes, Alfredo sauce, salsa, ricotta cheese, and taco seasoning; stir until evenly mixed.
Stir the drained pasta into the chicken and sauce mixture until well coated, then spread the mixture into the prepared baking dish.
Sprinkle the grated Parmesan cheese evenly over the top of the casserole.
Cover the dish and bake for 50 to 60 minutes, until the casserole is bubbly and heated through.
