Preheat the oven to 450° F. Heat a 10" skillet over medium heat and add the cream of chicken soup (undiluted) and the frozen mixed veggies. Heat until bubbly, stirring frequently, and cook 5 to 8 minutes or until the vegetables are cooked to your liking. Stir in the pepper and soy sauce, then gently fold in the chicken. The skillet will be full, so be careful. Remove from the heat and set aside.
In a large bowl, add the flour and cut the shortening into the flour with two forks (or a pastry blender) until the crumbs are the size of peas. Add in the milk, salt, garlic powder, chives, and cheese and stir until just combined. The dough should be soft, so you may add additional milk if necessary. Drop the dough by heaping spoonfuls onto the top of the chicken mixture.
Place the skillet on a rimmed baking sheet or pizza pan and bake for 10 to 12 minutes, or until the pie is bubbly and the biscuits are golden brown.