Preheat oven to 350°. Grease a 12-cup muffin tin with cooking spray; set aside.
In a large bowl, whisk together flour, cornmeal, baking powder and 1 teaspoon salt.
In another large bowl, whisk together milk, 1/4 cup cream of chicken soup and egg. Pour the wet ingredients into the dry ingredients; whisk to combine. Fill each prepared muffin cup 2/3 full with the cornbread batter.
In another large bowl, stir together chicken, mixed vegetables, remaining cream of chicken soup, poultry seasoning, remaining 1/4 teaspoon salt and pepper. Set aside.
In a large skillet, heat olive oil over medium heat. Add onion; cook until golden and tender, 3-4 minutes. Add garlic; cook until fragrant, 30-60 seconds. Stir vegetables into the chicken mixture. Spoon 1-2 tablespoons of filling over each batter-filled muffin cup.
Bake 25-30 minutes or until golden brown. Let cool in the pan 5 minutes; remove to serve.