Preheat oven to 400 degrees. Lightly spray 9x13 glass dish with non stick cooking spray and set aside.
Slice all zucchinis lengthwise and scoop out seeds to create a valley in each half zucchinis. Place into prepared baking dish and sprinkle with salt and pepper. Bake for 30 minutes.
Meanwhile, make the enchilada sauce. Pour oil into small saucepan and heat over medium heat. Sprinkle in flour and whisk. Cook down 1 minute before whisking in chicken stock. Pour in liquid and whisk to remove lumps. Stir in seasonings and simmer 5 minutes. Reduce heat to low.
For the filling, stir 1 1/2 cups grated cheddar cheese together with cream cheese, chicken, cumin, salt and pepper and chicken stock until moist and all ingredients are equally distributed.
Once zucchini boats are done baking and are tender, divide filling into each zucchini. Top with as much hot enchilada sauce as you'd like and then top with remaining cheddar cheese. Bake another 10 minutes until warmed through and broil the last 2 minutes to brown the tops. Remove from the oven, cool 5 minutes and serve.