1. Heat the olive oil in a large skillet over medium-high heat. Add the ground beef and diced onion and cook, breaking the meat apart with a spatula, until the beef is browned and the onion is softened.

2. Drain off any excess grease from the skillet, then stir in the minced garlic and cook for 30 seconds to 1 minute, just until fragrant.

3. Sprinkle the chili powder, smoked paprika, ground cumin, kosher salt, and black pepper over the beef mixture. Stir well to coat, then add the Worcestershire sauce, tomato sauce, and beef broth. Simmer for 1 to 2 minutes to blend the flavors, then remove from the heat.

4. Lightly grease a 5- to 6-quart slow cooker. Add the potato chunks in an even layer on the bottom of the crock.

5. Top the potatoes with the drained kidney beans and corn, then pour the diced tomatoes with green chiles (and their juices) over the top. Spoon the seasoned beef mixture evenly over everything. Gently stir once or twice to combine without breaking up the potatoes too much.

6. Cover and cook on LOW for 6 to 7 hours, or on HIGH for 3 to 4 hours, until the potatoes are fork-tender and the casserole is bubbly around the edges.

7. Taste the sauce and adjust the seasoning with additional salt and pepper if needed. Sprinkle the shredded cheddar and Monterey Jack cheese evenly over the top, cover, and cook on LOW for 10 to 15 minutes more, until the cheese is completely melted.

8. Top with diced red bell pepper and chopped parsley or green onions. Serve hot, with a dollop of sour cream on each serving if desired.