Brown the ground beef with the diced onion and bell pepper in a large skillet over medium-high heat, about 5-6 minutes.
Stir in the taco seasoning, then add the rice, diced tomatoes, and broth.
Bring to a boil, then reduce heat to low, cover, and simmer for 18-20 minutes, until the rice is tender.
Stir in the frozen corn during the last 5 minutes of cooking.
Remove from heat, sprinkle the cheese over the top, cover, and let sit for 2 minutes to melt.
Serve topped with sour cream, green onions, and avocado.