Spray 10-inch cast-iron pan with non-stick cooking spray and unroll 1 pie crust to cover the bottom of the pan. Set aside.
Preheat the oven to 400 degrees F.
Sprinkle the chicken tenders with paprika, sage, oregano, salt and pepper.
Heat a separate skillet (any) over medium-high heat and add the olive oil. When the oil begins to swirl, add the seasoned chicken and saute until cooked through, about 4 minutes on the first side and 3 minutes on the second side.
Remove the chicken to a plate with tongs, leaving the oil in the pan. Rest the chicken for a few minutes, and then chop into ½-inch cubes. Add chicken to the prepared 10-inch cast-iron pan on top of the pie crust.
To the same pan that the chicken was cooked in, add the chopped onions and peas and carrots and sprinkle with salt and pepper.
Stir and cook until the onions become tender, 3 to 5 minutes. Add the garlic and cook until fragrant, about 1 minute longer. Sprinkle in the flour and stir until the flour dissolves into the vegetables and juices. Add the chicken stock and raise to a simmer, stirring until thickened.
Once the liquid has thickened, stir in the heavy cream. Season with salt, if needed.
Add the liquid and vegetables to the 10-inch cast-iron pan on top of the chicken.
Unfold the pie crust and place over the top of the filling, tucking the excess edges inside the pan. Brush the crust evenly with the egg wash.
Using a knife, gently cut 3 vents in the top of the crust. Place in the oven and bake until the crust is golden brown, about 20 minutes.