Heat a large skillet over medium-high heat. Toss the cubed chicken with the olive oil, 2 teaspoons Italian seasoning, salt, and pepper.
Add the seasoned chicken to the hot skillet and cook, stirring occasionally, about 5 minutes until mostly cooked through.
Add the chopped shallot, garlic, and butter to the skillet and cook until fragrant, about 1 minute.
Stir in the dry orzo, fresh thyme, and the remaining 2 teaspoons Italian seasoning; cook, stirring, until the orzo is lightly golden, about 2 minutes.
Pour in 1 1/2 cups water and bring to a boil. Reduce heat and simmer for 5 minutes.
Stir in the milk or heavy cream and the Dijon mustard, then add the jarred artichokes. Simmer briefly to combine.
Fold in the baby spinach, grated Parmesan, and lemon zest and cook until the spinach is wilted and the orzo is al dente, about 6–8 minutes more.
Adjust seasoning with salt, pepper, and chili flakes to taste. Serve topped with plenty of fresh basil and extra Parmesan if desired.