Preheat the oven to 400 degrees. Start by combining all of the ingredients for the crust except for the cheddar cheese in a mixing bowl. Blend on high until smooth and creamy. Stir the cheddar cheese into the crust mixture, and set aside. Next, add 1 tablespoon of olive oil and 2 tablespoons of butter to a skillet over medium-high heat on the stove. Place the onion and celery into the skillet, and sauté for a few minutes until they begin to soften. Mix the green beans and shredded chicken into the veggies in the skillet on the stove. Sprinkle the Italian seasoning and garlic powder for the filling into the skillet, and stir to combine well. Mix in the heavy whipping cream and chicken broth to the filling mixture in the skillet, and then add salt and pepper to taste if desired. Continue to cook the mixture down until it thickens, and most of the liquid has been absorbed. Pour the filling mixture into the bottom of a greased 9×9 casserole dish. Place the crust mixture by spoonfuls on top of the filling, and carefully spread it out into an even layer with a spatula or your fingers. Bake the pot pie for 20-25 minutes until browned and bubbling.