Cook pasta according to package until al dente; reserve 1 cup pasta water before draining.
Meanwhile, melt butter in large skillet over medium; sauté garlic about 1 minute until fragrant.
Add cream, broth, tomatoes, Italian seasoning, and pepper flakes; simmer.
Stir in Parmesan until melted and smooth; add chicken and cook about 3-4 minutes until heated through.
Toss pasta in sauce; add reserved water as needed to desired consistency.
Season with salt and pepper to taste; garnish with basil and serve immediately.