Combine petite diced tomatoes, black beans, corn, chicken broth, salt, black pepper, green onions, garlic powder and cumin in slow cooker.
Season chicken with salt and lay on top.
Cook on low for 6-7 hours or on high for 4 hours.
Half hour before serving, remove chicken and shred. Return chicken to slow cooker and stir to combine.
Serve over rice and garnish with toppings of choice: salsa, chopped cilantro, lime wedges, avocado slices.