Heat a large skillet over medium heat and cook the ground beef, breaking it up and stirring frequently, until fully browned.
Drain any excess grease from the skillet.
Add taco seasoning and the amount of water called for on the seasoning packet to the cooked beef; stir to coat evenly.
Transfer the seasoned beef to a 6‑quart slow cooker.
Pour in the salsa, drained corn, drained and rinsed black beans, and beef broth, then stir to combine.
Add the frozen cheese tortellini and stir until distributed through the mixture.
Cover and cook on low for 2½ hours, stirring once every hour to prevent sticking.
Sprinkle the shredded cheese over the top, replace the lid, and let sit about 5 minutes, or until the cheese melts.
Serve warm topped with sour cream and chopped fresh cilantro.