Preheat oven to 400*F, place oven rack on the bottom third of the oven, and spray 9 inch pie plate with a nonstick spray.
To make filling, Spray skillet with a nonstick spray and set over medium heat. Add chicken and onion, cook and break apart chicken until its no longer pink (takes around 8 mins). Add garlic, curry powder, cinnamon, allspice, salt, and pepper, stir and cook until fragrant (around 1 min). Stir in tomato sauce and simmer until the mixture has thickened (around 5 mins). Once thick, transfer mixture into a bowl and stir in spinach, feta, and egg whites.
Lay one filo sheet at the bottom of the pie plate, spray with a nonstick spray, repeat this three times, lightly spraying each sheet. (Cover remaining filo with a damp paper towel to avoid it drying out). Spoon in filling and then top pie with the remaining 4 filo sheets (make sure to layer and lightly spray each sheet as done before).
Roll up edges of the filo towards the center of the pie, forming a 1 1/2 inch wide rim. Bake pie on bottom rack of oven until filo is golden brown ( around 30-35 mins), then let stand for 5 mins.
