In a small bowl, stir sour cream and adobo sauce to combine; set aside.
Cut each roll in half through the sides. Spread cut sides with butter.
In a large skillet over medium heat, toast rolls cut side down until golden brown, about 2 minutes per roll. Spread cut sides of bottom buns with ¼ cup beans, then sprinkle each with ¼ cup cheese.
In same skillet over medium-high heat, heat oil. Add onion and cook, mostly undisturbed, until slightly charred, 2 to 3 minutes. Add chicken and cook, stirring occasionally, until chicken is golden brown and crisp in parts, 3 to 4 minutes. Stir in taco seasoning and cook, stirring, until fragrant, about 1 minute more.
Divide chicken mixture among bottom buns. Top with avocado, a layer of chips, tomatoes, lettuce, pickled jalapeños, and cilantro. Spread reserved chipotle cream on cut sides of top buns and close sandwiches.