Bring a large pot of salted water to a boil. Add penne pasta and cook according to package instructions until al dente. Drain and set aside.
While pasta cooks, season chicken thighs evenly with salt and black pepper on both sides.
Heat olive oil in a large skillet over medium-high heat. Add chicken thighs and cook for 5-6 minutes per side, until golden brown and cooked through (internal temperature 165°F). Remove chicken from skillet and set aside to rest.
In the same skillet, reduce heat to medium. Add butter and minced garlic; sauté for 1 minute until fragrant, stirring constantly to prevent burning.
Add red pepper flakes and canned diced tomatoes with their juices. Stir to combine and bring to a simmer. Cook for 5 minutes to reduce slightly.
Pour in chicken broth and heavy cream. Stir and simmer for another 5 minutes until sauce thickens slightly.
Slice the cooked chicken thighs into strips or bite-sized pieces.
Add cooked pasta and sliced chicken back into the skillet with the sauce. Toss gently to coat everything evenly.
Remove skillet from heat and stir in grated Parmesan cheese and chopped fresh basil.
Serve immediately, garnished with additional Parmesan or basil if desired.