Preheat oven to 400 degrees F. Line a baking sheet with parchment paper. Place chicken breasts in a 2- to 3-quart slow cooker. Sprinkle with taco seasoning, then add cream cheese cubes and water. Cover and cook for 6 to 8 hours on low, or for 4 to 6 hours on high. With two forks, shred the chicken. Add cheddar cheese and stir to coat the chicken evenly. Spoon chicken mixture into the center of a tortilla. Roll up tortilla tightly and place on baking sheet. Repeat with remaining chicken mixture and tortillas. Spray taquitos generously with olive oil spray. Bake for 8 to 12 minutes, or until tortillas are crisp.