Preheat oven to 400°F. Spray an 8x8-inch glass baking dish with cooking spray. Set aside.

Make 5-6 slices, about ¾ inch apart, into the top side of the chicken, being careful not to cut all the way through.

Combine ranch seasoning mix, dried parsley flakes, salt, and black pepper in a small bowl.

Season each chicken breast with the seasoning mix, ensuring the mixture gets into the slices.

Gently open each of the slices and insert a piece of Canadian bacon and zucchini slices. Feel free to add more if needed.

Transfer the stuffed chicken breasts to the prepared baking dish, filling side up. Top each with shredded Monterey jack cheese, pressing some into the crevices.

Bake for 25 minutes or until the internal temperature reaches 165°F and the cheese is browned. Rest for 2-3 minutes before serving.