Step 1: In a large pot or Dutch oven, heat the olive oil over medium heat. Add the chopped onion and cook until softened, about 5 minutes. Stir in the minced garlic and jalapeño (if using) and cook for another minute until fragrant.
Step 2: Add the chicken breasts or thighs to the pot. Cook for 5-7 minutes, browning lightly on all sides. The chicken does not need to be cooked through at this stage.
Step 3: Stir in the cumin, chili powder, oregano, black pepper, and salt. Cook for 1 minute, allowing the spices to toast and become fragrant.
Step 4: Add the rinsed and drained beans, diced green chilies (with their liquid), and chicken broth to the pot. Bring the mixture to a simmer.
Step 5: Once simmering, reduce the heat to low, cover, and cook for 15-20 minutes, or until the chicken is thoroughly cooked and easily shreds.
Step 6: Carefully remove the cooked chicken from the pot and shred it using two forks. Return the shredded chicken to the chili.
Step 7: Add the softened cream cheese cubes and milk (or half-and-half) to the pot. Stir continuously until the cream cheese is fully melted and incorporated, creating a smooth, creamy broth.
Step 8: Taste and adjust seasonings as needed. Serve hot with your favorite toppings and enjoy!