In a medium-sized enamel-coated pot or similar, add the olive oil and heat on medium.
Place bite-sized raw chicken in a bowl and season with Kosher salt, black pepper, and Italian seasoning. Cook in preheated oil until browned. Remove browned chicken and set aside.
Add a little more olive oil to the pot if needed, and add the diced onion, diced pepper, chopped sun-dried tomatoes, and garlic to the pot, cover, and let them sweat for a minute.
Stir in orzo and coat with the cooked onion and pepper mixture.
Add the chicken broth and browned chicken, stir to combine, cover, and simmer for 5 minutes. Remove the lid, stir the mixture, and scrape up any bits that you feel on the bottom of the pot. Cover and let simmer for another 5 minutes. Repeat by stirring the mixture and scraping up any bits that you feel on the bottom. Taste the orzo for doneness. The orzo should be tender; the total cooking time is 10-12 minutes.
Turn the heat off the pot and stir in Greek yogurt until incorporated into the orzo mixture.
Fold in the spinach until it wilts.
Serve immediately, garnished with Parmesan cheese and red pepper flakes if desired.