Combine fire-roasted tomatoes, minced onion, minced garlic, chopped poblano peppers, chopped chipotle peppers, chopped walnuts, red lentils, bulgur, chili powder, and smoked paprika in the Instant Pot.
Secure the lid, set to 'Soup' mode for 30 minutes, and allow natural pressure release for 10 minutes before quick releasing any remaining pressure.
Stir in the pumpkin puree and rinsed black beans.
Taste and season with additional salt, pepper, or chili powder as needed.
Serve hot, garnished with avocado slices, lime wedges, fresh cilantro, or with tortilla chips.
If the chili is too thick, thin it out with 1/4 to 1/2 cup of water or vegetable broth until desired consistency is reached.