PREHEAT oven to 350º F. Grease 13 x 9-inch baking dish.
COOK pasta according to package directions. Drain; set aside.
MELT butter in small saucepan over medium heat. Stir in flour, salt and black pepper until smooth. Gradually stir in evaporated milk and water. Cook, stirring constantly, until mixture comes just to a boil and thickens. Remove from heat; set aside.
SPREAD 1/3 of white sauce on the bottom of prepared dish. Top sauce with half of pasta, 1/3 of sauce, half of creamed corn, half of pimentos and half of poblano. Sprinkle with cheddar cheese. Repeat with remaining pasta, sauce, corn, pimientos and poblano. Top with Chihuahua cheese. Cover with foil.
BAKE for 20 minutes. Remove foil and bake an additional 5 minutes.