Season the cubed chicken with salt, black pepper, and 2 teaspoons Italian seasoning.
Heat 2 tablespoons olive oil in a large skillet over medium-high heat. Add the chicken and cook, stirring occasionally, until mostly cooked through, about 5 minutes.
Add the chopped shallot, chopped garlic, and 2 tablespoons butter to the skillet and cook, stirring, until the shallot softens, about 1–2 minutes.
Stir in the dry orzo and 1 tablespoon fresh thyme, and sprinkle the remaining 2 teaspoons Italian seasoning; cook, stirring, until the orzo is lightly toasted, about 2 minutes.
Add 1½ cups water and bring to a boil. Reduce heat and simmer for about 5 minutes, stirring occasionally, until the orzo has absorbed some liquid.
Stir in 1 cup milk or heavy cream and 2 teaspoons Dijon mustard, then add the quartered marinated artichokes. Simmer and stir for a few minutes to combine.
Add the baby spinach, 3/4 cup grated Parmesan, and 2 teaspoons lemon zest; cook, stirring, until the spinach wilts and the orzo is tender, about 6–8 minutes.
Taste and adjust seasoning with salt, pepper, and chili flakes as desired. Serve topped with fresh basil and extra Parmesan if desired.
