In a large pot over medium heat, melt the butter until bubbly. Add the diced onion, minced garlic, and diced green pepper, stirring frequently for about 3 minutes.

Once the vegetables are tender, add in the softened cream cheese and mash slightly to help it blend into the vegetables, stirring for about 1-2 minutes until smooth.

Pour in the diced tomatoes with green chilies, chicken broth, and whipping cream. Stir well to combine all ingredients.

Open the fajita seasoning and sprinkle it into the pot, mixing thoroughly. Allow the soup to simmer over medium-low heat for about 20 minutes.

Add the cooked chicken and stir until well incorporated and heated through, approximately 3-5 minutes.

Ladle the soup into warm bowls and garnish with sour cream, shredded cheese, avocado, and fresh cilantro.