HEAT oven to 400oF. Melt butter in a 10-inch cast iron skillet or deep oven-proof skillet. Add onion and cook 5 minutes, stirring frequently. Add chicken and cook 6 minutes or until chicken is no longer pink inside. Remove from heat and stir in cream style corn and corn kernels.
COMBINE corn bread mix, milk and egg in a medium bowl. (Batter will be stiff.) Stir in 1/2 cup cheese. Using a large spoon, scoop batter into 6 mounds over the chicken mixture.
BAKE 25 to 30 minutes or until bubbly and corn bread is golden brown. Remove from oven and top with remaining 1/2 cup cheese. Let stand 5 minutes for cheese to melt.
ARRANGE spinach evenly among 6 shallow bowls. Spoon one sixth of the chicken mixture and one corn biscuit over spinach in each bowl. Sprinkle evenly with bacon, if desired.