Prepare Chicken: Generously rub the taco seasoning onto chicken breasts, until well coated. Place in a slow cooker and top with enchilada sauce, canned tomatoes, lime juice, cilantro, and green chilies.
Cook on low for 6 hours, stirring once or twice.
Remove chicken from crockpot and shred with two forks.
Mix together the cornstarch and cold water. Then add to slow cooker and stir.
Return the shredded chicken to the slow cooker and cook for an additional half an hour.
Meanwhile, heat oven to 350°F.
Flatten out the bread slices using a rolling pin. Then, using a 2-inch round cookie cutter, cut 2 rounds from each slice of bread (this depends on the size of your cookie cutter and muffin cups).
Spray 12 (preferably mini) muffin cups with cooking spray. Place each bread round in a muffin cup, pressing into the corners. Bake 5 minutes, or until crisp.
Fill each bread cup with a tablespoon of the chicken mixture.
Evenly distribute the shredded cheese among the scoops.
Broil under low heat for 1-2 minutes, until cheese is melted.
Top each “tortilla” cup with a dollop of sour cream, a few diced tomatoes, and some more cilantro. Optionally, you can top each cup with a few crumbles of queso fresco.