If desired, sauté the onion and garlic: Heat olive oil in a large skillet over medium heat. Add diced onion and cook until softened, about 5-7 minutes. Add minced garlic and cook for another minute until fragrant. Transfer the sautéed mixture to the slow cooker.

Place the boneless, skinless chicken breasts (or thighs) at the bottom of a 6-quart (or larger) slow cooker. If you sautéed the aromatics, add them now. If not, simply add the raw diced onion and minced garlic directly to the slow cooker.

Add the rinsed and drained Great Northern beans, diced green chiles (undrained), chicken broth, frozen corn, ground cumin, chili powder, dried oregano, cayenne pepper (if using), salt, and black pepper to the slow cooker. Stir gently to combine, ensuring the chicken is mostly submerged.

Cover and cook on LOW for 6-8 hours or on HIGH for 3-4 hours, until the chicken is cooked through and easily shreddable.

Carefully remove the cooked chicken from the slow cooker and place it on a cutting board. Using two forks, shred the chicken into bite-sized pieces. Return the shredded chicken to the slow cooker.

Add the softened, cubed cream cheese and half-and-half (or heavy cream) to the slow cooker. Stir well until the cream cheese is fully melted and incorporated, creating a creamy, smooth chili. Taste and adjust seasonings as needed.

Ladle the warm Slow Cooker White Chicken Chili into bowls. Serve immediately with your favorite toppings such as fresh cilantro, shredded Monterey Jack cheese, a dollop of sour cream, diced avocado, and crunchy tortilla strips.