Preheat the oven to 375 degrees F (190 degrees C). Spray a 9x13-inch casserole dish with cooking spray.

Heat a large skillet over medium-high heat. Add ground beef and start to brown, then add onion, garlic, and taco seasoning. Cook until beef is no longer pink, 5 to 7 minutes. Drain and discard any excess oil. Add beans, tomatoes, spinach, chicken broth, 1 cup Mexican blend cheese, rice, and salsa. Pour into the prepared casserole dish.

Bake in the preheated oven until rice is cooked, 45 to 50 minutes. Take out of the oven, sprinkle with remaining cheese, and bake until cheese is melted, about 10 minutes more.