Prepare the bell peppers by cutting the tops off and removing the seeds and membranes. Set them aside.
In a mixing bowl, combine the shredded chicken, black beans, corn, salsa, cumin, chili powder, salt, and pepper. Mix well until all ingredients are fully combined.
Stuff each bell pepper with the chicken and bean mixture, packing it down gently.
Place the stuffed peppers upright in the slow cooker.
Pour any remaining salsa over the peppers for added flavor.
Cover the slow cooker and cook on low for about 6 hours, or until the peppers are tender.
In the last 15 minutes of cooking, sprinkle the shredded cheese on top of the stuffed peppers, cover, and allow the cheese to melt.
Once cooked, carefully remove the peppers from the slow cooker and place them on a serving plate.
Garnish with fresh cilantro, if desired, before serving.