Crumble pork sausage into a large skillet over medium-high heat; cook and stir until no longer pink, 7 to 10 minutes. Drain and discard any excess grease. Return skillet to heat; add cream of chicken soup, French onion dip, green bell pepper, red bell pepper, and onion. Fold hash brown potatoes and 1 cup Cheddar cheese into the mixture; bring to a simmer.
Transfer sausage mixture to a 9x11-inch casserole dish; top with 1 cup Cheddar cheese. Cover dish with aluminum foil.
Bake in preheated oven for 30 minutes. Remove foil and continue baking until beginning to brown around the edges, about 15 minutes more.
