Instant Pot Chicken Tortilla Soup

Preheat oven to 350°. Turn Instant Pot to Sauté setting and heat oil. When oil is shimmering, add bell peppers and onion. Cook, stirring occasionally, until vegetables are starting to soften, about 5 minutes. Stir in garlic, oregano, cumin, and chili powder. Season chicken generously with salt and pepper then add to Instant Pot. Add remaining soup ingredients and close lid. Set Instant Pot to Soup setting and set timer for 7 minutes. Meanwhile, on a large baking sheet, toss tortilla strips with oil and a pinch of salt. Bake until golden, about 20 minutes.  When cooking is complete and air has been naturally released from Instant Pot, carefully remove lid and use tongs to remove chicken breasts onto a plate or cutting board. Using two forks, shred chicken. Stir chicken and cilantro into soup. Season with salt and pepper, to taste. Garnish soup with tortilla strips, avocado, and cheese to serve.