Dice the chicken breasts into bite-sized pieces and season with salt and pepper.
In a large pot, heat the olive oil over medium heat. Add the onion and garlic and cook until the onion is translucent, about 2 minutes.
Add the chicken and cook until browned on all sides and the thickest pieces reach 165°F, about 5–7 minutes.
Stir in the mixed vegetables, chicken broth, and dried thyme. Bring to a boil.
Add the egg noodles, ensuring they are submerged. Reduce the heat to low and simmer for 10–12 minutes, until the noodles are cooked.
Stir in the heavy cream over low heat until combined. Adjust salt and pepper, garnish with parsley, and serve.