In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until translucent.
Add the minced garlic and sliced chicken sausage to the skillet; continue sautéing for another 5-6 minutes until the sausage is browned.
Stir in the orzo pasta, chicken broth, and Italian seasoning. Bring the mixture to a boil, then reduce the heat to low, cover, and let it simmer for about 10-12 minutes, or until the orzo is tender and has absorbed most of the liquid.
Once the orzo is cooked, stir in the heavy cream, chopped spinach, and halved cherry tomatoes. Mix well and cook for an additional 2-3 minutes until the spinach is wilted and the tomatoes are heated through.