Preheat oven to 350. Cook Amy's Mac n' Cheese according to directions on package and add to a large bowl. Place zucchini on baking sheet and cook for 15-20 minutes, or slightly soft and let cool. scoop out as much flesh as possible from zucchini without breaking it. Combine tomato, corn, avocado and chili powder in a small bowl and add to cooked pasta, stir well. Spoon filling into zucchini without over-stuffing (you may have extra filling if your zucchini are smaller) and bake for 20-25 minutes.