Cook ground beef and sausage in a large pot over medium-high heat until lightly browned and crumbly; drain. Add chili powder, cumin, and coriander; cook and stir until fragrant, about 1 minute. Stir in onion and garlic; cook and stir until onion softened and turned translucent, about 4 minutes.

Stir in diced tomatoes, tomato sauce, kidney beans, chipotle peppers, salt, and black pepper; bring to a simmer, then transfer chili to a slow cooker. Cover slow cooker.

Cook on Low for 7 to 9 hours. Stir in tomato paste and cook 1 hour more.