Heat a large Dutch oven over medium-high heat. Add olive oil and when shimmering, add onion to the pan. Cook for several minutes until tender, stirring frequently. Add garlic and continue to cook until fragrant, a minute more. Stir in cumin, and chili powders, and cook until mixture looks dry, a minute or two.
Add the green chilis, beans, and chicken broth. Bring to a simmer, cover, and gently simmer for about 10 minutes. With a potato masher, mash beans to desired consistency. Add a little water to bring to a preferred consistency. Add chicken and simmer gently for about 10 more minutes.
Taste and adjust seasoning. Garnish with sour cream, cheese, cilantro, and green onions.
Any leftover chili may need to be thinned a bit with water when being reheated as the chili will thicken a bit upon standing.
Notes:
Find it online: https://frugalhausfrau.com/2017/08/18/easy-white-chicken-chili/