Heat olive oil in a large pan or skillet over medium-high heat. Add chicken strips and cook for 3-5 minutes, stirring occasionally, until starting to brown.
Add chopped onion and paprika powder, and sauté for 7-10 minutes, stirring occasionally, until chicken is cooked through and onion is soft.
Season with balsamic vinegar, sugar, salt, and pepper.
Reduce heat to medium, stir in sour cream and Worcester sauce, and simmer for 2-3 minutes, stirring occasionally, until sauce thickens slightly.