Season chicken breasts with salt, pepper, and Italian seasoning.
Heat olive oil in a large skillet over medium-high heat. Sear chicken for 3-4 minutes per side until golden brown. Remove and set aside.
In the same skillet, sauté diced onion and garlic for 2-3 minutes until fragrant.
Add orzo pasta and toast for 1-2 minutes, stirring constantly.
Pour in chicken broth and heavy cream. Return chicken to the skillet. Simmer for 15-20 minutes, stirring occasionally, until orzo is tender and the sauce thickens.
Stir in grated Parmesan cheese and fresh spinach. Cook until spinach wilts.
Serve hot, garnished with additional Parmesan and optional red pepper flakes or fresh basil.