If you're poaching the chicken, add 2 chicken breasts to a saucepan and cover with cold tap water. Bring to a boil and then reduce heat to let simmer for 20-25 minutes or until the chicken is cooked through. You can optionally add some flavoring to the water -- for this batch I added salt, pepper, onion and cilantro. Once cooked, set the chicken breasts aside to cool and then use two forks to shred them.
To make the Avocado Salsa Verde, start by removing the husks and stems from the tomatillos. Give them a good rinse and roast them in a 400F oven until they start to turn army green in color, approx. 10-15 minutes.
Add the roasted tomatillos to a blender along with 1/2 onion, 1 garlic clove, 10-12 sprigs cilantro, and 2 serrano peppers (or less if you want a milder version). Combine well and taste for heat level, adding more serrano if you want more heat. Add the flesh of the avocado to the blender and combine well. Salt to taste.
In a mixing bowl, combine the shredded chicken with the following ingredients: 2 cups shredded cheese, 1/4 onion finely chopped, 1/2 cup pickled jalapenos finely chopped, 2 teaspoons chili powder, 2 teaspoons Mexican oregano, 1 teaspoon salt, freshly cracked black pepper. Mix together well.
Add the tortillas to a plate and cover with damp paper towels. Microwave for 60 seconds or until the tortillas are soft and pliable.
Add 2-3 tablespoons of chicken mixture to each tortilla. Roll tight and place them seam side down on a baking sheet. Add a thin layer of oil to each Flauta before baking them (I used an olive oil sprayer).
Bake for 20 minutes in a 400F oven or until the edges are turning darker brown. Serve immediately with the Avocado Salsa Verde.