Heat the deep 12-inch skillet over medium heat. Cook the diced onion for 1–2 minutes.
Add the ground beef and break it into crumbles. Cook until no pink remains and the beef reaches 160°F (71°C). Drain the excess fat and return the skillet to the heat.
Stir in the taco seasoning, undrained tomatoes, drained corn, uncooked long-grain rice, and beef broth. Bring the mixture to a small boil.
Reduce the heat to a gentle simmer and cover. Cook for 20 minutes, stirring once after 10 minutes. If the rice remains firm, cover and cook for up to five minutes longer.
Stir the mixture and sprinkle the Colby Jack over the top. Cover and cook on low for about three minutes, until the cheese melts. Serve hot with the optional toppings.