Dice the celery ribs, onion, bell pepper, and jalapeños. Roughly mince the garlic cloves. Add all to the bottom of your slow cooker.
Slice your Spanish chorizo sausage into rounds, and add to the slow cooker. Add the chicken thighs, then the seasonings: chili powder, cumin, cayenne pepper. Add salt and pepper to taste.
Pour the cans of corn and green chilis into the slow cooker. Follow with the entire can of diced tomatoes, juice and all. Pour in the chicken broth and 1/4 cup of cilantro. Stir together.
Cover slow cooker with lid and turn heat to high. Cook for four hours.
After four hours, your chicken will be cooked through and the liquid should be boiling. Take two forks and shred the chicken right in the slow cooker, being careful not to scratch the sides of your glorious slow cooker in the process.
Add the uncooked rice and canned black beans to the pot and stir to spread throughout. Cover slow cooker with lid once more, and set timer to 30 minutes on high.
Check your rice at 20 minutes. If it's not finished, check it at 25 minutes. If still not complete, let the slow cooker go until its 30-minute timer is finished.
When the rice is cooked, fluff with a fork. Serve immediately in bowls, and top each with the remaining 1/4 cup cilantro.