Cook the chicken. Place the chicken thighs in the Instant Pot with enough water to cook them. Pressure cook until tender and cooked through. Remove the chicken and reserve about 1 to 1½ cups of the cooking liquid. Shred the chicken and set aside.
Sauté the garlic. Turn the Instant Pot to Sauté. Add the olive oil and minced garlic. Sauté for about 1 minute, just until fragrant.
Build the chili. Add the diced tomatoes with their juices, corn, about 1½ cans' worth of cooked black beans, chili seasoning, diced chipotle pepper, and adobo sauce. Stir well.
Add the chicken and broth. Stir the shredded chicken into the chili. Add about 1 to 1½ cups of the reserved chicken cooking liquid, adjusting the amount to reach your desired chunky chili consistency.
Season and simmer. Season with salt and black pepper to taste. Bring the chili to a gentle simmer and let it cook for about 5 minutes, stirring occasionally, so the flavors can come together.
Make it creamy. Turn off the heat and stir in the heavy cream until completely incorporated. Taste and adjust the salt and seasoning as needed. If the chili is thicker than you'd like, add a little more chicken broth or water.
Serve. Ladle into bowls and top with shredded cheddar cheese and fresh jalapeño slices, if desired.
