Season & sear chicken: Season thighs with chili powder, salt, and pepper. Heat olive oil in a large skillet over medium-high. Cook chicken until golden, about 4 minutes per side. Remove and set aside.
Sauté aromatics: Lower heat to medium. Add onion and poblano pepper; cook until soft (~5 minutes). Add garlic; cook 1 more minute. Stir in tomato paste to coat.
Build the base: Pour in chicken broth, scraping up bits from the pan bottom. Add diced tomatoes, black beans, corn, quinoa, cumin, oregano, cayenne, salt, and pepper.
Cook with chicken: Return chicken to the skillet. Bring to a boil, then reduce heat to simmer, cover, and cook for 20 minutes.
Finish cooking: Uncover and cook until quinoa is tender and chicken is cooked through, about 10–15 minutes more.
Add final touches: Remove chicken, stir in cilantro and lime juice into the quinoa.
Serve: Plate with chicken, and top with avocado, sour cream, and lime wedges as desired.
