Bring a pot of water to boil to prepare pasta. Drain and place back into pot.
Preheat pan to low medium heat with 1 tbsp olive oil to cook onion and asparagus. Remove from pan, add 2 teaspoons more oil and add in garlic and chicken to cook until chicken juices run clear and is no longer pink. Add dried oregano and salt + pepper to taste.
Toss veggies + chicken into pot with pasta. Add in 2 tablespoons olive oil and mix together. Add 1/3 cup parmesan if desired!