In large dutch oven or heavy pot, heat olive oil on medium high until shimmery, about 30 seconds.
Add chicken and onion to pot and cook, stirring occasionally, until lightly browned - about 5 minutes.
Stir in bell pepper and jalapeno, cook until chicken is browned, another 5 minutes.
Stir in herbs and spices, sour cream, and stock.
Whisk or stir soup vigorously to combine.
Bring to a boil, and then reduce to low.
Stir in cheese, making sure to stir quickly so cheese incorporates into soup instead of sinking to the bottom to burn on the pan.
When cheese is fully incorporated, remove from stove and serve immediately.
Top with shredded Monterey jack cheese and chives, if desired.