Heat oil in a large Dutch oven or oven-proof stockpot over medium heat. Add onion and saute 2 minutes. Add chicken and saute 5 to 7 minutes, until browned on all sides. Remove 1/2 the cooked chicken for later in the week, cover and refrigerate.
In a small bowl, combine flour, thyme, salt, pepper, and paprika. Add flour mixture to the chicken and stir to coat. Stir in carrots, celery, potatoes, tomatoes, chicken broth, wine, and Dijon mustard and mix well. Bring mixture to a boil. Cook until vegetables are tender.
Transfer stew to a clean 2-quart casserole dish and stir in corn.
Place pie crust on top of casserole and pinch around the edges to seal the crust to the dish. Brush the top with beaten egg and prick the surface 1 or 2 times with a sharp knife or fork to allow steam to escape during cooking.
Place casserole dish on baking sheet and bake 8 to 10 minutes, until crust is golden.