Preheat oven to 350°F
Season the chicken thighs. Get a pan very hot, add oil, and sear the chicken thighs for 2-3 minutes per side. Remove from pan to a baking dish, cover, and bake at 350°F for 20-30 minutes until 150-160°F internal temp. Remove from oven and leave covered for 20-30 minutes to cool slightly.
Deglaze the pan and sauté the onions, peppers, cumin, and oregano. After a couple of minutes add the garlic. Sauté on low-medium until tender, 5-10 minutes. Remove from range and let cool.
Shred the chicken and add to a large bowl. Add the onion, garlic, and peppers. Add the cilantro and cheese and mix well. Add ¼-cup of the enchilada sauce or more to make a consistent mix. Taste and adjust seasoning.
Grease a 9"-x-13" pan. Add ⅓-cup of the sauce to the bottom.
For assembly, take a tortilla and add ~⅓-cup of the chicken mixture to a tortilla and roll. Put in the pan, seam side down. Repeat with the remaining tortillas.
Spread the remaining chicken mixture down the middle of the tortillas.
Pour the remaining sauce over the enchiladas.
Sprinkle with more cheese.
Cover with foil and bake at 350°F for 25 minutes. Remove foil and bake an additional 10 minutes.
Remove from oven and let set for 10-15 minutes before serving. Serve with sour cream and salsa.