Preheat a pan over medium high heat with some olive oil. Season the chicken with salt and pepper and sear in the pan to brown on both sides. Remove from pan.
Add in the onions and cook about 5 minutes, scraping the bottom of the pan to get any of the bits of browned chicken incorporated into the dish.
Add in the garlic and cook 2 minutes. Add the broth, almond milk, and sundried tomatoes to the pan, then add the chicken back in.
Bring to a simmer and reduce heat to medium low. Slowly simmer for about 20 minutes until the chicken is cooked through.
Add the spinach and stir to combine. Cook about 2-5 minutes until wilted.
Taste and add more salt and pepper to taste. Serve.