Pat chicken dry and cut into bite-size pieces.
Season chicken with salt, pepper, and Italian seasoning.
Heat 1 Tbsp olive oil in a large skillet over medium-high heat.
Add chicken and cook 6-8 minutes until golden and cooked through.
Remove chicken and set aside.
Lower heat to medium and add remaining olive oil and butter.
Sauté garlic and red chili flakes for 30 seconds until fragrant.
Stir in chicken broth, heavy cream, Italian seasoning, and sun-dried tomatoes.
Whisk in Parmesan cheese until melted.
Add cooked chicken and tortellini to the sauce.
Cook uncovered for 5 minutes, stirring occasionally, until tortellini is cooked and sauce thickens.
Transfer to serving bowls and garnish with fresh basil and additional Parmesan.