Preheat oven to 325°F. Season the chicken breasts with salt & pepper, & a sprinkle of chili powder. In a dutch oven or large, oven safe pot, heat oil on Medium High & brown chicken. Approximately 3 minutes each side. Remove chicken & set aside.
With pot still on medium high, throw onion, garlic & jalapeno in & cook for approximately 5 minutes.
Deglaze with 6oz of beer, scraping up all the brown bits from the pan, & drink the rest.
Combine the rest of the ingredients & the rest of the Chili Powder, with the onions, peppers & garlic & place the chicken in. Pour in chicken stock to just cover the chicken, if necessary, & bring to a simmer. Tear up 2-3 corn tortillas & toss into pot.
Cover, & place pot in oven for 2.5 hours or until chicken is fork tender.
Remove chicken from the pot & set aside. Use an immersion blender, or carefully pour braising liquid into a blender & blend until smooth. Taste. Season with Maggi seasoning & pepper to taste.
Plate chicken in a shallow bowl, ladle over a spoonful of sauce, & garnish with cilantro to taste. Serve with corn tortillas.