Place pepper halves over fire or on broiler pan rack, cut sides down. Broil or char until skins are mostly charred. Remove peppers to a saucepan, cover and let stand 10 minutes.
Pull charred skin from peppers (some will remain), then cut peppers in 1 1/2-inch pieces.
Preheat oven to 350 degrees F. Have a 9 x 13-inch baking dish ready.
Spread 1/4 cup salsa over bottom of baking dish. Top with 3 noodles placed crosswise, leaving 1 inch between each.
Whisk sour cream, milk, egg and flour in a medium bowl until blended (mixture will be thin). Pour 2/3 cup sauce over the noodles to cover. Scatter chicken, then 1/4 cup cilantro over top. Sprinkle with 1/2 cup shredded Monterey Jack cheese and dot with 2 tablespoons salsa. Cover with 3 more noodles and another 2/3 cup sauce. Top with yellow peppers, 1/2 cup cheese, the corn and 1/4 cup cilantro. Top with 3 more noodles and the remaining sauce, salsa and cheese. Cover with foil.
Bake 40 to 45 minutes until noodles are tender. Let stand, covered, for 10 minutes. Uncover and sprinkle with remaining cilantro.