1Season both sides of the chicken generously with salt and pepper.
2In a large oven safe skillet, heat the avocado oil over medium heat and cook chicken breasts for 6-8 minutes per side until reaching 165F; remove and set aside to cool.
3Add butter, diced onion, and diced jalapeño to the skillet and cook until tender and translucent.
4Add salt, chili powder, cumin, garlic, and flour to the skillet and cook while stirring for 1 minute.
5Gradually add milk 1/4 cup at a time, stirring until incorporated, then add enchilada sauce and diced green chilis.
6Simmer uncovered over low heat for 5 minutes while shredding the cooked chicken.
7Add shredded chicken and white beans to the skillet, mix, add tortilla pieces, and cook for 2-3 minutes until heated through.
8Spread mixture evenly, top with shredded cheese, and broil in the oven until melted and golden brown.