Prepare a slow cooker with nonstick cooking spray. In the bottom layer the onions and chicken. Top the chicken with the taco seasoning, garlic, and poblano peppers.
Dot the cream cheese over the top. Cover the slow cooker and cook on low for 6 to 7 hours.
Shred the chicken thighs with two forks. Stir the chicken and vegetables until the cream cheese is melted. Serve topped with cheese and freshly chopped cilantro.