Add the chili powder, cumin, oregano, paprika, cayenne pepper, salt, and black pepper. Stir for one minute. Then add the fire roasted tomatoes, vegetable broth, black beans, kidney beans, corn, and optional green chilis. Stir until well combined. Bring to a boil and reduce heat and let it simmer uncovered for 40 minutes, stirring occasionally. It should thicken up.