Chicken Tacos
OK, this will be very non-specific. As usual, for me - I tend to cook by taste, and measurements are very approximate when I cook. 
NOT low fat, but quite simple. You can try substituting olive oil and some apple juice in place of the butter, but that’s an experiment I haven’t yet tried. Do so at your own risk. 
Takes about a half hour.
4 Chicken Breasts, deboned and skinned.
About a cup of finely diced Onion.
About 6oz Butter.
(Olive oil enough to easily cover bottom of the pan when heated should be about right, if you’re swapping out the butter. It will taste different)
About 2 Tablespoons diced Chipotle peppers in Adobo Sauce.
(Be careful here. A mistake with this ingredient will turn your taco meat into HazMat)
About 3 Garlic Cloves, diced or crushed.
1/4 to 1/2 cup Orange Juice.
(This adds both sweetness and acid - you shouldn’t need any other citrus. Pulp or no pulp is up to you) 
1 to 1 1/2 Tablespoon Worchestershire Sauce.
(This adds the flavor of dark meat)
1 Tablespoon Spicy Mustard.
1/4 cup finely-chopped Cilantro.
Corn Tortillas.
Additional taco garnishes and fixings, as you like. I personally like avacado, fresh onions, corn salsa, and sour cream. YMMV. 
Use a deep frying pan or shallow pot, with a lid.
Start the butter melting, add the onions, chipotle peppers, and garlic. Cook on medium heat until onions are golden brown. Place chicken breasts in pan and cover. Cook about 10 minutes on one side. Flip breasts over, and re-cover. Cook until the meat is white all the way through - internal temp 160ºf or higher.
Remove chicken from pan, and set aside to cool a bit.
Add cilantro, orange juice, worchestershire sauce, and mustard. Cook, stirring occasionally, until the sauce remaining in the pan is reduced to a thick slurry.
Meanwhile, shred the chicken with forks. (You can cube it, too, but shredding works better, IME)
Once the sauce is reduced, add the chicken back into the pan, and stir to pick up and absorb the sauce. Keep stirring until all sauce is taken up, or until you’re bored.
Reduce heat to keep warm, and re-cover.
Toast the corn tortillas in a dry frying pan or over a low gas flame until firm-but-pliable. Add chicken and garnish as you like.
Notes:
~ Seriously. Be careful with the chipotles - Too much can make something that only a masochist would like. Too little, and there’s no ‘bite.’
~ Follow the chicken cooking steps fairly precisely, and you’ll have nice juicy, moist chicken - no drying out. 
~ The Worchestershire Sauce adds notes of dark meat to the sauce. Adjust as you care - It’s not strictly required, but without it, you get ‘bland.’
~ The Mustard adds a spicy note.
~ The orange juice adds both acid and sweetness - the contrast just works.
~ No additional salt added, other than what’s in the Adobo and Worchestershire Sauces, which is, admittedly, probably plenty enough and then some. No pepper added, no chili powder, no cumino or coriander - Very straight forward.
DO adjust the seasoning amounts - I frankly did NOT follow exact measures. I adjust to taste as I cook - The measures I list above are all approximate, but will put you in the ballpark. After that, you’re on your own - Have fun!