Preheat the oven to 350 degrees f.
Thaw and lightly cook the frozen veggie mix either in the microwave or on the stove top. In a large bowl, add the shredded chicken and heated veggie mix and stir till well incorporated.
14 ounces Fiesta blend frozen veggies, 24 ounces Shredded chicken
In 2 stacks of 12, wrap the corn tortillas in a tea towel or paper towel and warm in the microwave till soft and pliable, about 45-60 seconds.
24 Corn tortillas
In a casserole dish, lay flat one tortilla and add about 1.5 ounces of the shredded chicken and veggie mix to the tortilla. Then add about .5 ounces of the cotija cheese.
10 ounces Cotija cheese
Gently roll up the stuffed tortilla and lay folded side down. Repeat this step for the remaining tortillas and chicken mix, assembling approximately 12 enchiladas for each casserole dish.
Pour about 10 ounces of the homemade enchilada sauce on each casserole dish of finished enchiladas, reserving about 8 ounces of sauce to use for those who want more sauce after baking. Sprinkle each casserole dish full of enchiladas with 4 ounces of shredded cheddar cheese.
8 ounces Shredded cheddar cheese
Bake the enchiladas in the oven for 20-30 minutes, till cheese is melted and enchiladas are warmed through.
Serve immediately, spooning on more homemade enchilada sauce if desired.