Heat a large pot over medium heat and add the ground beef. Cook until browned, breaking it up with a spoon as it cooks.
Add the diced onion and minced garlic to the pot. Stir and cook for 3 to 4 minutes until the onion softens.
Sprinkle in the chili powder and cumin. Stir for 1 minute to coat the meat and release the spices.
Pour in the pumpkin puree, kidney beans, diced tomatoes, and beef broth. Stir everything together until well combined.
Bring the mixture to a simmer, then reduce the heat to low. Cook uncovered for 20 minutes, stirring occasionally.
Taste and add salt and pepper as needed. Ladle into bowls and top with shredded cheddar cheese, sour cream, chopped green onions, and roasted pumpkin seeds.