Place 2 large boneless, skinless chicken breasts on large plate. Sprinkle salt over both sides of each chicken breast, then place chicken breasts in Instant Pot insert.
Add 2 10-ounce cans diced tomatoes with green chiles, 1 14.5-ounce can low-sodium chicken broth, 1 cup chopped onion, 2 teaspoons garlic powder, 1 teaspoon onion powder, 1-3 teaspoons chipotle pepper powder, 1 teaspoon cumin, 2 teaspoons chili powder, 1 teaspoons dried oregano, 1 teaspoon smoked paprika, and 2 medium zucchini to Instant Pot and gently stir to incorporate ingredients.
Secure lid on Instant Pot with valve in Sealing position. Set Instant Pot to Manual High Pressure for 18 minutes. Instant Pot will pressurize, then cook time will begin.
When cook time ends, Natural Release pressure for 10 minutes. After 10 minutes, immediately and carefully Quick Release remaining pressure and remove lid from Instant Pot.
Transfer chicken breasts to cutting board and set aside.
Set Instant Pot to Sauté mode. Add 1 14-ounce can unsweetened, full-fat coconut milk to Instant Pot and stir to incorporate.
Dice chicken breasts into bite-sized pieces, or shred chicken breasts to small pieces. Once all chicken has been diced or shredded, return chicken to Instant Pot and stir to incorporate.
Portion soup into serving bowls. If desired, top each serving with fresh avocado slices, thinly sliced red onions, chopped fresh cilantro, and fresh lime juice, then serve hot.