• To roast poblanos: Position oven rack about 5 inches from the heat source; preheat broiler. Line the broiler pan with foil. Broil whole poblanos, turning once, until starting to blacken, 8 to 12 minutes. Transfer to a paper bag and let steam to loosen skins, about 10 minutes. When the poblanos are cool enough to handle, peel, seed, stem and coarsely chop; set aside. • Meanwhile, heat oil in a large soup pot or Dutch oven over medium-high heat. Add chicken and cook, turning occasionally, until lightly browned, 3 to 5 minutes. Transfer to a plate and set aside. • Reduce the heat to medium and add onion, bell pepper, green beans and garlic. Cook, stirring, until beginning to soften, 5 to 7 minutes. Stir in chili powder and cumin and cook, stirring, until fragrant, about 30 seconds. Stir in broth, beans, tomatoes and the chopped poblanos; bring to a boil. Reduce heat to maintain a simmer and cook, stirring occasionally, until the vegetables are tender, about 15 minutes. • Add the reserved chicken and juices, chard (or spinach) and corn; return to a simmer and cook for 15 minutes more to heat through and blend flavours. • Top each portion with 1 tablespoon each cilantro and lime juice; serve with lime wedges. • To make ahead: Prepare through Step 4 and refrigerate for up to 3 days or freeze for up to 6 months; add cilantro and lime juice just before serving.