spaghetti
extra-virgin olive oil
yellow onion, chopped
red bell pepper, seeds and ribs removed, chopped
boneless, skinless chicken breasts, cut into 1" pieces
Kosher salt
Freshly ground black pepper
chili powder
unsalted butter
all-purpose flour
whole milk
low-sodium chicken broth
shredded cheddar, divided
Chopped fresh parsley, for serving