Combine ground beef and onion in a large skillet over medium heat; cook and stir until beef is browned, about 5 minutes.
Step 4 Step 5
Transfer beef and onion to a slow cooker. Stir in diced tomatoes, black beans, corn, nopales, tomato paste, chili powder, sugar, chipotle pepper, garlic powder, cumin, salt, and pepper.
Step 6 Step 7
Cook on Low until flavors combine, about 4 hours.