Combine tomatoes, chicken, chiles, broth, onion, garlic, cumin, salt and pepper in the Instant Pot; mix well.
Secure lid and move pressure release valve to Sealing position. Press Manual; cook at high pressure 9 minutes. When cooking is complete, use natural release for 10 minutes, then release remaining pressure.
Remove chicken to plate; shred into bite-size pieces when cool enough to handle. Stir into soup.
Press Sauté; add tortillas and cilantro to soup. Cook and stir 2 minutes or until heated through. Top with cheese, avocado and squeeze of lime juice.