Step 1: Heat olive oil in a large pot or Dutch oven over medium-high heat. Season chicken with salt and pepper, then cook until browned and cooked through, about 6-8 minutes. Remove chicken and set aside.
Step 2: In the same pot, melt butter over medium heat. Add garlic and red pepper flakes, cooking until fragrant, about 1 minute.
Step 3: Pour in chicken broth and heavy cream, stirring to combine. Bring to a simmer.
Step 4: Add tortellini to the pot, stirring to coat. Cover and cook according to package directions, about 8-10 minutes, until tortellini is tender.
Step 5: Return chicken to the pot, stirring to combine. Stir in Parmesan cheese until melted and sauce is creamy.
Step 6: Remove from heat and stir in parsley. Season with additional salt and pepper if needed. Serve immediately.