In a large bowl, combine the flour, salt, pepper, paprika, and garlic powder. Add the chicken to the bowl and toss to coat all the pieces evenly. Remove the chicken from the bowl and tap off the excess flour mixture.
To a large nonstick skillet over medium heat, add the olive oil and butter. Once hot, place the seasoned chicken cubes into the skillet and cook for 8-10 minutes, flipping halfway, until golden brown and cooked through. Chicken is fully cooked when it reaches an internal temperature of 165°F. Remove from the pan and tent to keep warm.
To the same skillet, add the onion, cherry tomatoes, and sun-dried tomatoes. Cook until softened (about 5 minutes). Add the garlic and cook for 30 more seconds.
Reduce the heat to low and add the chicken broth, heavy cream, Gruyere, parmesan cheese, red pepper flakes, Italian seasoning, and salt. Stir well to combine all the ingredients. Let the sauce simmer until thickened slightly (about 8 minutes).
While the sauce is simmering, cook the tortellini according to package instructions.
Add the cooked tortellini and chicken to the sauce. Stir to coat.
Cover the skillet. Simmer for 5 minutes to allow the flavors to meld together.
Garnish with grated parmesan cheese.