Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Season chicken pieces with salt and pepper, then cook 5-7 minutes per side until golden. Transfer to a plate once browned.

Add diced onion to the same pot and sauté 3-4 minutes until softened and fragrant. Stir in minced garlic and cook 1 minute until aromatic, scraping up browned bits from the bottom.

Pour in chicken broth and diced tomatoes with their juices, bringing the mixture to a gentle boil. Add uncooked orzo pasta, dried Italian seasoning, and thyme, stirring occasionally to prevent sticking.

Return the cooked chicken to the pot and reduce heat to medium, simmering 12-15 minutes until orzo reaches al dente texture. The cozy one pot chicken orzo recipe allows pasta to absorb broth while chicken finishes cooking through.

Stir in fresh spinach and frozen peas, cooking 2-3 minutes until spinach wilts completely. Remove from heat and stir in heavy cream and Parmesan cheese until smooth.

Taste and adjust seasonings with additional salt, pepper, or Italian seasoning as needed. Let it rest 5 minutes before serving, allowing flavors to settle.