Pre-heat your oven to 375 and make sure your pie crust is out coming to room temperature.
Take your cubed chicken breast and cook it in a large skillet with olive oil until it starts to brown.
About halfway through cooking the chicken, add your frozen pearl onions. Then when those soften, add your peas.
Once the peas soften, lower the heat and add the corn and BBQ sauce. Taste and add salt and pepper as needed. Mix together and let simmer for a few minutes while you prepare your potatoes.
Mash your sweet potatoes with the garlic, butter, cinnamon, chili powder and milk. Start with a little bit of the milk and keep adding as you need it (you may not use it all your you may use more)
Pour your chicken mixture into the pie crust and top with mashed potatoes.
Bake for 35-40 minutes. I recommend putting the pie on a baking sheet in case it spills over a little.