Pat the chicken breasts dry and season both sides with chili powder, cumin, salt, and pepper.
Heat olive oil in a large skillet over medium-high heat. Add the chicken and cook for 5-6 minutes per side, until golden brown and cooked through to 165°F. Remove from skillet and set aside.
Reduce heat to medium. Add the diced onion to the same skillet and cook until softened, about 4-5 minutes.
Stir in the diced green chiles with their liquid and chicken broth. Bring to a simmer and cook for 2-3 minutes.
Reduce heat to low and stir in the heavy cream. Add the shredded Pepper Jack cheese and stir until completely melted and smooth, about 2-3 minutes.
Return the chicken to the skillet and spoon the sauce over the top. Simmer for 2-3 minutes until heated through.
Garnish with fresh cilantro before serving.
Notes
Pat chicken dry before seasoning for the best sear.
Use freshly shredded Pepper Jack cheese for the smoothest sauce.
Keep heat low when melting cheese to prevent separation.
Chicken thighs can be substituted but may need 2-3 extra minutes cooking time.