Heat oil in a saute pan over medium-high heat. Add the onions and saute a couple of minutes until they start to turn translucent.
As the onions continue to cook, add the red bell peppers, the chicken and the minced chipotles in adobo sauce. Sprinkle the mixture with the salt, ancho and garlic powders and Mexican oregano*. Stir gently to combine.
Add the chicken broth or stock enough to moisten the mixture. You can add more if needed to keep the mixture from dying out. Once the mixture is heated through transfer to warmed tortillas.
Top each taco with a little shredded cheese and sliced jalapeno's.
*If you don't have Mexican oregano (which is much milder) then use half the amount of common Greek oregano.