Reduce heat to medium; add onion and poblanos. Cook, stirring occasionally, until softened, about 5 minutes. Stir in garlic, cumin, coriander, and chili powder, and cook until fragrant, 1 minute more. Stir in canned chiles. Add chicken back to pot along with broth and juices, scraping up bits from the bottom of the pan. Bring to a boil then reduce heat to medium-low and simmer, partially covered, until chicken is cooked through and flavors meld, about 15 minutes.