Cut the chicken breasts into roughly 1-inch pieces so they cook evenly.
Heat 1–2 tablespoons olive oil in a Dutch oven or large deep skillet over medium heat.
Add the chicken pieces, garlic powder, oregano, and salt and pepper; cook, stirring occasionally, until the chicken is mostly cooked through, about 5 minutes.
Add the sun-dried tomatoes and cook briefly until heated through and the chicken is nearly done.
Add the dry orzo and stir, toasting it in the pot for 1–2 minutes.
Pour in 1 quart chicken broth and stir to combine. Bring to a gentle simmer.
Simmer, stirring occasionally, for 10–15 minutes until the orzo is tender and has absorbed most of the liquid.
Remove from heat and stir in the Boursin cheese and fresh spinach until the cheese melts and the spinach wilts.
Taste and adjust seasoning with salt and pepper as needed. Serve topped with optional freshly grated Parmesan.
