Preheat the oven to 350°F and lightly spray a 9x13-inch baking dish with cooking spray.
Cook the angel hair pasta according to package directions until al dente, then drain well.
In a large bowl, combine the chopped cooked chicken, cream of chicken soup, sour cream, onion powder, garlic powder, undrained Rotel, and 1/2 cup of the shredded cheddar; mix until evenly combined.
Add the drained pasta to the chicken mixture and stir until the pasta is evenly coated.
Spread the pasta mixture into the prepared baking dish, then sprinkle the remaining 1 1/2 cups cheddar cheese evenly over the top and finish with the French fried onions.
Bake uncovered for 25 to 30 minutes, until the casserole is bubbly and the topping is golden; remove from oven and let sit a few minutes before serving.