Combine 1 can tomatoes and green chiles, chicken, and 1 cup water in a saucepan. Drain remaining 1 can tomatoes and green chiles, and add liquid to saucepan. Set drained tomatoes and green chiles aside.
Bring chicken mixture to a boil; reduce heat, and cook 10 to 15 minutes. Remove chicken, and strain cooking liquid, reserving 2 1/2 cups liquid and diced tomatoes and green chiles. Cool chicken slightly, and chop.
Melt butter in saucepan over medium heat; whisk in flour until smooth. Cook, whisking constantly, 1 minute. Gradually whisk in reserved tomato liquid until blended. Add cream cheese, and cook, whisking constantly, 5 minutes or until sauce is thickened. Spread 1 cup sauce into bottom of a lightly greased 13- x 9-inch baking dish.
Press spinach between paper towels to remove excess moisture. Stir together spinach, chicken, half of reserved diced tomatoes and green chiles, cottage cheese, sour cream, and 1 cup cheese blend. Spoon mixture down center of each flour tortilla; roll up. Place, seam side down, in dish. Top with remaining sauce.
Bake at 350° for 25 to 30 minutes; sprinkle with remaining 1 cup cheese, and bake 5 more minutes. Sprinkle with remaining tomatoes and green chiles. Sprinkle with toppings.