Cut the onions in half lengthwise and then into strips. Do the same with the Poblano peppers.
Heat 2 tablespoons of olive oil in a large, heavy bottomed pan. Add the onions and peppers. Sprinkle with a large pinch of salt and a little black pepper.
Bring the heat up until the vegetables start to sizzle well, then reduce the heat to medium low. Cook, stirring frequently, until the onions and peppers are very soft.
Remove from the pan and set aside.
While the onions and peppers are cooking, prepare the chicken by cutting it into bite-sized pieces.
Using the same pan as for the onions and peppers, add one tablespoon of olive oil and the chicken. Sprinkle with the oregano and cumin. Cook over medium heat until cooked through and lightly brown.
Return the onions and peppers to the pan.
Add the chicken stock or broth. Bring to the boil, then reduce the heat and simmer while you prepare the tortilla strips.
Preheat the oven to 375 degrees.
Cut the tortillas into strips. Place on a baking sheet with the remaining 2 tablespoons olive oil. Sprinkle with a large pinch of salt and large pinch of oregano.
Toss the strips with the oil so that they are evenly coated. Spread into a single layer on the baking sheet. Cook, stirring every 5 minutes until nicely browned.
When ready to serve, assemble the serving bowls: Using 4 oven-safe containers, layer each with a small amount of tortilla strips, a ladle of soup, additional tortilla strips, and two ounces of the Sargento 4 Cheese Mexican blend.
Switch the oven to broil. Place the prepared bowls under the broiler until the cheese melts and is bubbly. Garnish with sour cream and fresh cilantro.