Saute. Heat vegetable oil (2 tablespoons) in a large heavy bottom pot over medium heat. Stir in chopped onion (2 cups) and bell pepper (1) and cook until softened, about 5 minutes. Add cumin (2 teaspoons), chili powder (1 teaspoon), and salt (1 teaspoon). Stir to coat the veggies in seasoning, and cook until fragrant (about 2 minutes).
Simmer. Add the enchilada sauce (12 Ounces), chicken broth (2 cups), salsa (8 ounces), and chicken breast (1 pound). Stir to incorporate. Bring soup to a boil, then reduce to a simmer. Simmer uncovered for 30-40 minutes -- your soup is done once the internal temp of your chicken reaches 165 F (this will vary depending on how thick your chicken is).
Chicken. Use tongs to remove cooked chicken onto a cutting board. Once cool enough to handle, shred or chop into bite-sized pieces.
Finishing touches. Add the sour cream (1 cup) and shredded cheddar (1 cup), and stir until these ingredients dissolve. Add the chicken, cilantro (1/4 cup), and green onions (1/4 cup). Top with toppings of choice, and enjoy!