Preheat heavy skillet to medium for a couple minutes. Add oil, chicken, and garlic and cook 5 minutes, stirring to turn as chicken cooks.
Add marjoram and potatoes and stir. Cover and cook 10 minutes (still on medium), stirring halfway through, making sure that potatoes aren't sticking.
Preheat oven to 425 F.
Uncover skillet and turn heat off. Add cream soup, broth, vegetables, cheese, and cream. Stir to combine well.
Prepare bottom crust in 9 x 9 baking dish or large pie pan. Pour filling mixture onto bottom crust. Add top crust and press top and bottom crusts together to seal.
Place on sheet pan before putting in the oven. Cook for 30 minutes or until crust is nicely brown and filling is bubbly.
NOTE: This pot pie is perfect for make-ahead dinners. Simply follow all the instructions for the pot pie up to putting it in the oven (don't cook it yet). Cover with foil and freeze for up to 2 months. Once ready to cook, remove from the freezer 30 minutes before cooking. Preheat oven to 425. Bake covered for 30 minutes, then uncover to bake 30 minutes more to finish cooking and to brown.