Thaw spinach and preheat oven to 375°F.
Chop chicken into cubes of about 1 square inch ( or 2.5 cm squared).
Cook chicken in skillet with tbsp of vegetable oil until mostly cooked through. Do not cook through completely or chicken will get dry.
Cut gouda into strips and melt it in 1/4 cup of fat free milk. (I usually do this in the microwave by cooking and stirring every few minutes).
While cheese is melting, mix together the chicken and spinach in a casserole dish so that spinach is dispersed evenly throughout. If you have more chicken than spinach, add a bit more spinach keeping in mind it will shrink as it gets cooked!
As soon as cheese is melted pour immediately over the chicken and spinach. Do not mix again! The cheese will melt through the layers as it cooks.
Melt the butter and add to it the breadcrumbs.
Using your fingers or a fork, crumble together the breadcrumb and butter mixture and sprinkle evenly over the top of the dish.
Sprinkle remaining 2 tbsp of breadcrumbs and chili powder evenly over dish.
Bake covered for about 35-40 minutes.