Add the chopped spinach, frozen corn, fire roasted tomatoes, salsa and ½ the cheese to the skillet and stir.
In a large skillet add the ground beef and start browning over medium high heat. Sprinkle the taco seasoning over the beef and break it up with a wooden spoon. Cook until meat is no longer pink and has started to brown, about 5 minutes.
Preheat oven to 375 F degrees. Spray a 9x13 inch casserole dish with cooking spray.