Heat the skillet over medium heat. Once hot, add the ground beef and cook until browned, breaking it up with a wooden spoon, about 5-7 minutes.
Drain any excess fat from the skillet if necessary.
Add the diced onion and bell pepper to the skillet. Sauté for 3-4 minutes until the vegetables are softened.
Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Add the diced tomatoes (with juice), corn, chili powder, cumin, salt, and pepper. Mix well and let it simmer for about 5 minutes, allowing the flavors to meld.
Stir in the cooked rice or quinoa and mix until everything is well combined and heated through, about 2-3 minutes.
Sprinkle the shredded cheese on top and cover the skillet for 1-2 minutes until the cheese melts.
Remove from heat, garnish with fresh parsley if desired, and serve hot.