Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Add sliced chicken sausage and cook for 3-4 minutes until browned on both sides. Transfer the sausage to a plate and set aside.
In the same skillet, add the remaining olive oil followed by diced onion. Sauté for 2-3 minutes until translucent before adding minced garlic along with Italian seasoning and red pepper flakes if using; cook for an additional 30 seconds until fragrant.
Add uncooked orzo pasta to the skillet with onions and garlic; toast it lightly by stirring frequently for about 1-2 minutes until slightly golden. Pour in chicken broth while scraping up any browned bits from the bottom of the pan; bring this mixture to a simmer.
Lower heat to medium-low after it reaches a simmer; cover the skillet and let it cook for about 8 minutes allowing orzo to absorb most of the liquid. Once time is up, add broccoli florets back along with browned chicken sausage; stir everything together before covering again.
Cook covered for another 4-5 minutes until broccoli is tender-crisp yet vibrant in color while orzo has soaked up more broth. Remove from heat then stir in grated Parmesan cheese alongside fresh lemon juice; season with salt & pepper according to your taste preferences.
Before serving, garnish with freshly chopped parsley. Enjoy warm straight from the pan!