Start by dicing the boneless chicken into bite-sized pieces. Remove the florets from the broccoli heads, and spiralize the stems into noodles if desired. Mince the garlic and dice the onion.
In a large skillet, heat the 3 tablespoons of olive oil over medium-high heat. Once hot, add the diced chicken. Season with salt and pepper to taste. Sauté for about 5-7 minutes, or until the chicken is cooked through and no longer pink.
Next, add the diced onion and minced garlic to the skillet. Cook for an additional 2-3 minutes until the onion becomes translucent. Stir in the broccoli florets and spiralized noodles. Cook until the broccoli is tender, about 3-4 minutes.
Pour in the 1/2 cup low-sodium chicken broth, then sprinkle in the 1/4 teaspoon dried thyme, 1/4 teaspoon dried parsley, and 1/4 teaspoon onion powder. Stir everything together and let it simmer for a couple of minutes to allow the flavors to meld.
Reduce the heat to low and sprinkle the 1 cup shredded sharp cheddar cheese and 1/2 cup shredded havarti cheese over the skillet. Cover the skillet with a lid and let the cheese melt for about 3-4 minutes.
Once the cheese is melted and bubbly, remove the skillet from heat. Serve your Chicken and Broccoli Skillet Bake warm, garnished with additional parsley if desired.