Sprinkle chicken cubes with salt and pepper evenly on both sides; set aside.
20 ounces boneless skinless chicken breasts, salt and pepper
Heat a large sauté pan over medium-high heat and drizzle with olive oil. Add the seasoned chicken to the pan and sauté until browned, about 7-8 minutes stirring occasionally. Remove chicken from pan; set aside.
1 tablespoon extra virgin olive oil
To the hot pan, add the onion slices, jalapeño and garlic. Sprinkle with a pinch of salt and pepper and sauté until tender and slightly caramelized, about 5-6 minutes stirring frequently. Add tomatoes to the pan and season with another pinch of salt and pepper. Continue sautéing until tomatoes are softened, about 3-4 additional minutes.
2 cloves garlic, 1 medium onion, 1 jalapeño, 1 large tomato
Return chicken and any residual juices to the pan and stir well. Heat until chicken is warmed through, about 3-4 minutes. Check for seasoning and adjust accordingly. Garnish with fresh herbs before serving.
1/4 cup cilantro
Notes
To keep mild, remove seeds and pith from the jalapeño.