In a large pot over medium heat, heat oil.
Add onion and jalapeño and cook, stirring, until softened, about 8 minutes.
Add garlic, oregano, and cumin and cook, stirring, until fragrant, about 1 minute.
Add chicken, broth, and chiles; season with salt and pepper.
Bring to a boil, then reduce heat and simmer, uncovered, until chicken is tender and cooked through, 10 to 12 minutes.
Transfer chicken to a plate and shred with 2 forks.
Add beans to pot and bring to a simmer.
Cook, smashing about one-quarter of beans with a wooden spoon, until slightly thickened, about 10 minutes.
Add corn and shredded chicken and cook, stirring, until heated through, about 1 minute more.
Remove from heat and stir in sour cream.
Ladle chili into bowls.
Top with avocado, cilantro, chips, and cheese.