Toss chicken with salt, pepper, garlic powder, paprika, and cornstarch until coated.
Heat tomato oil over medium-high. Sear chicken in a single layer 3 min without moving, toss, 2 more min until golden and 165°F / 74°C. Transfer to a plate.
Same pan, add garlic, stir 60 sec. Add tomato paste, stir 90 sec until brick red. Add sun-dried tomatoes, stir 30 sec.
Add wine to scrape the pan bottom. Reduce 90 sec. Add stock, reduce by 2 min.
Reduce to medium-low. Add cream, red pepper flakes, and Italian seasoning. Simmer gently for 2 min.
Add fresh tortellini directly to sauce. Stir gently. Cover. Simmer for 3 min.
Remove the lid. Check tortellini tender with a slight bite. If not ready, cover 1 more min.
Add spinach. Stir until wilted for 60 sec. Remove from heat.
Add Parmesan in 3 stages off the heat, stirring fully between each.
Return chicken. Fold gently. Taste for salt. Scatter basil off the heat. Serve immediately.