Heat a grill pan over medium-high heat. Sprinkle chicken with 1/4 teaspoon salt and pepper. Coat pan with cooking spray. Add chicken to pan; cook 6 minutes on each side or until done.
While chicken cooks, heat a large skillet over medium-high heat. Add chorizo; cook 1 minute, stirring to crumble. Add remaining 1/4 teaspoon salt, onion, and carrot; cook 2 minutes, stirring occasionally. Add bell peppers; cook 1 minute or until crisp-tender. Add stock; cook 2 minutes or until liquid almost evaporates, scraping pan to loosen browned bits. Spoon chorizo mixture over chicken; top with cilantro.