Bring a large pot of salted water to a boil. Cook the tortellini according to package directions until al dente. Drain and set aside.

In a small bowl, mix together paprika, Italian seasoning, salt, and pepper. If you marinated the chicken, drain it from the buttermilk. Otherwise, pat the chicken pieces dry with paper towels, then toss them in the spice mix. Sprinkle the flour over the chicken and stir until evenly coated.

In the same pot (nonstick) used for the tortellini, heat 3 tablespoons of the oil from the sun-dried tomatoes over medium heat for about 30 seconds. Add the basil sprig and minced garlic, stirring for another 30 seconds.

Increase the heat to medium-high and add the seasoned chicken. Cook, stirring occasionally, until the chicken is cooked through and no longer pink, about 6–8 minutes. If needed, add a little more sun-dried tomato oil to prevent sticking. When the chicken is almost done, remove the basil sprig and stir in the chopped sun-dried tomatoes. Cook until the chicken is fully cooked.

Reduce the heat to low. Add the drained tortellini back into the pot with the chicken. Gently stir for 1–2 minutes to warm through, then remove from heat.

Stir in the basil pesto and 1–2 tablespoons of the sun-dried tomato oil to loosen the sauce. Taste and adjust seasoning with salt, pepper, and red pepper flakes if desired.

Divide the skillet mixture among plates. Garnish with fresh basil leaves and a sprinkle of grated Parmesan cheese. Serve immediately.