In a skillet, brown the ground beef over medium heat, breaking it into crumbles. Drain excess fat.
Add chopped onion and bell pepper to the skillet with the cooked beef. Sauté until vegetables are tender.
Stir in the black beans and corn, heating them through.
Add the cooked rice to the skillet, mixing it well with the beef and vegetable mixture.
Sprinkle the taco seasoning over the mixture and stir to combine. Let it simmer for a few minutes to absorb the flavors.
Transfer the mixture to a greased casserole dish, spreading it evenly.
Pour the salsa over the top of the casserole, spreading it evenly.