Bring a large pot of salted water to a boil. Prepare an ice bath by filling a large bowl with ice and water.
Blanch the chopped broccoli rabe in the boiling water for 2-3 minutes until bright green and slightly tender. Using a slotted spoon, transfer the broccoli rabe to the ice bath to stop the cooking process. Drain and set aside.
In a large skillet, heat a drizzle of olive oil over medium heat. Add the chicken Italian sausage and cook until browned and cooked through, about 8-10 minutes. Remove the sausage from the skillet and set aside.
In the same skillet, add a bit more olive oil if needed, then add the minced garlic and red pepper flakes. Sauté for about 1 minute until fragrant.
Return the cooked sausage to the skillet. Add the blanched broccoli rabe and pour in the chicken broth. Bring to a simmer and cook for an additional 2-3 minutes to allow the flavors to meld together. Season with salt and pepper to taste.
Meanwhile, cook the orecchiette pasta according to the package instructions until al dente. Drain and set aside, reserving 1/2 cup of pasta water.
Add the cooked orecchiette pasta to the skillet with the sausage, broccoli rabe, and broth. Toss everything together, adding reserved pasta water as needed to loosen the sauce and coat the pasta evenly.
Serve hot, garnished with grated Parmesan