When the oil is hot, add chicken cubes, season with salt and pepper. Cook, stirring occasionally until chicken is browned and just cooked through, 4-5 minutes.
Cut bacon into bite-sized pieces. Cook in a 12-inch skillet until crispy. Remove cooked bacon from skillet using a slotted spoon, keeping 1-2 tablespoons of bacon fat.
Add chicken pieces to the hot skillet, season with salt and pepper. Cook on medium-high heat for 2-3 minutes.
Add in chopped onion and garlic. Saute for another 2 minutes, scraping the bottom of the skillet to prevent anything from sticking.
Deglaze the pan with chicken stock. Add tortellini, Italian seasoning, pepper flakes, salt, and pepper. Give everything a good stir, cover, and cook for 5-6 minutes until the pasta is 3/4th cooked. (stir in between to prevent the pasta from sticking at the bottom).
Lower heat. Add cream, chopped sundried tomatoes, crispy bacon, and freshly grated parmesan cheese. Toss everything well, taking care not to break the tortellinis. Let it simmer for a minute, for the sauce to come together. You may add a splash of warm chicken stock to make it a little extra saucy.
Serve with a garnish of fresh parmesan.