In a large skillet over medium heat, heat oil. Add onion and cook 2 minutes, then add ground beef and cook until no longer pink, 6 minutes, breaking up with a wooden spoon as it browns. Drain fat.
Move beef to one side of skillet and add white rice to other side. Cook 2 minutes, then add fire-roasted tomatoes, black beans, corn, green chilis, cumin and chili powder. Season with salt and stir to combine, then pour over chicken broth.
Bring to a simmer, cover, and cook 20 minutes.
Top with cheddar and Monterey Jack and cover to let melt, 2 to 3 minutes.
Garnish with cilantro and serve.