Craig, You seem to be the resident taco guru here so Im going to ask you if you were asked to make shredded chicken taco's, what ingredients would you add to the chicken to get authentic flavor. I will be using chicken thigh's.
"Authentic flavor" could mean a lot of things depending on who you ask. To me, it usually means simple. The way I would prepare the meat for a shredded chicken taco would make something like you described. Chicken thigh is the best cut for a shredded chicken taco. I would call this "authentic:"
I'd take 4 or 5 dried guajillo chilies, take the stems off, cut them open, take out the seeds, and toast them on a hot dry cast iron skillet for 10 seconds/side or so until they are fragrant. You might need to press them down on the skillet with a spatula. Cut them in 1" strips. You should be able to find these in a large supermarket. If not, dried New Mexico chilies or dried California chilies would be a good substitute.
Brown 6-8 skin-on thighs in some vegetable oil in the (large) cast iron skillet*. Get them nice and dark golden brown as this is the only color they are going to get, and brown = flavor. Juices sticking to the bottom of the pan and browning is good - very good.
Add boiling hot water to come up about 1/2 way on the thighs. Put in your toasted chili strips, a couple cloves of crushed garlic, and one large bay leaf broken into three pieces (always break your bay leaves). Depending on my mood, I might or might not add a peeled, diced, and seeded fresh tomato. I would NEVER NEVER NEVER add canned tomato! Add a couple turns of freshly cracked black pepper and a tiny pinch of salt. That's it. You almost don't need any salt, and you can always add more later. Make sure everything you add is pushed down into the water.
Cover it with a piece of foil and put it into a 350F oven until the chicken is ready to shred (~30-45 min). You would really have to try to overcook it. Just don't let the pan go dry - if it get's low, add some boiling hot water. When it is ready, shred it and add back come of the cooking liquid to make it moist but not wet. Taste the liquid first. If it is really concentrated, you might want to thin it with a little bit of water. Save any leftover liquid. It makes great rice another day.
Serve it with anything you like, but for authentic, this would be served on two stacked steamed corn tortillas with diced white onion and cilantro and a slice of lime on the side for the eater to squeeze on it if s/he likes. Perhaps a slice of grilled jalapeno or a grilled green onion. Maybe a slice of avocado. Probably not a sauce with a moist shredded meat like this.
*A cast iron skillet really works best for this - you could use something else. You could also brown in bathes in a skillet and bake in a roasting pan if you wanted to make a larger batch.
