Preheat oven to 350 degrees. Spray a 9 by 12-inch baking dish with cooking spray.
Place the block of Velveeta cheese in the middle of the baking dish. Add the macaroni around the cheese. Distribute the can of tomatoes and chilies over the top. Sprinkle with the Mexican blend cheese, pour the cream all over, sprinkle with salt and bake 25 minutes.
Melt the butter in a large skillet over medium heat. Add the breadcrumbs and cook, stirring occasionally, until golden brown.
Stir the macaroni mixture in the baking dish and continue to bake for another 20 minutes. Sprinkle the toasted breadcrumbs over the mixture and bake for another 5 minutes.