The main ingredient in the sauce is tomatillas, I grew these over the summer so there was no problem finding them. But when they aren't in season and your closest grocery store doesn't have the best produce selection you need to improvise. So I was about to give up and just do a plain tomato base when I found a tomatillo salsa. The salsa had most of the ingredients that I would have put in the sauce, minus the roasted tomatoes so I decided to give it a try. The result...delicious! Now I must say if you have the time and ingredients I would still recommend the homemade sauce.
10-12 corn or flour tortillas*
3/4 rotisserie chicken, shredded
1-15oz. Can fire roasted tomatoes
1 1/2 cups tomatillo salsa, such as Frontera Grille
3/4 cup sour cream
3/4 cup shredded Colby-jack cheese
In a blender or food processor blend the salsa, tomatoes and sour cream. Take about half of the salsa mixture and mix with the chicken. Spread some of the salsa mixture on the bottom of a 13x9 baking dish. Fill each tortilla with about a 1/4 cup of the chicken mixture. Roll and place seam side down in the baking dish.
Pour the remaining salsa mixture over the tortillas and then top with cheese.
Bake at 400 degrees until hot and bubbly. About 30 minutes.
*Note: I think that corn tortillas taste best with this, but they get mushy if you freeze then cook later. So if you plan on making this ahead of time and freezing I would recommend using the flour tortillas.