Cook the ground beef and onion in a large skillet over medium heat until the beef is completely browned, 7 to 10 minutes; season with salt and black pepper.
Drain excess grease from the ground beef mixture; transfer to a casserole dish.
Stir the cream of chicken soup, chicken noodle soup, and instant rice through the ground beef mixture; season again with salt and black pepper.
Bake in the preheated oven until the edges begin to bubble, 40 to 45 minutes.
