Mix green salsa, diced tomatoes with green chile peppers, white beans, chicken broth, corn, onion, oregano, cumin, salt, and black pepper together in a slow cooker. Lay chicken breasts atop the mixture.
Cook on Low until the chicken shreds easily with 2 forks, 6 to 8 hours.
Remove chicken to a cutting board and shred completely; return to chili in slow cooker and stir.
