Start by patting the chicken breast dry with paper towels and seasoning it generously with salt, pepper, and half of the dried oregano. Allow to rest for about 5 minutes.

Heat a tablespoon of olive oil in a large skillet over medium-high heat. Add the seasoned chicken and sear for 5-6 minutes until golden-brown. Flip and cook for an additional 3-4 minutes until fully cooked. Transfer to a plate and keep warm.

In the same skillet, add another tablespoon of olive oil and minced garlic, sauté for about 30 seconds. Toss in the diced red bell pepper and sliced yellow squash, cooking for 4-5 minutes until tender.

Add the sweet cherry tomatoes, cooking for an additional 2 minutes until they begin to burst. Return the seared chicken, folding in fresh spinach, remaining oregano, and red pepper flakes. Sauté for 2-3 minutes until spinach wilts.

Remove from heat and zest a lemon over the stir fry. Adjust seasoning with more salt and pepper if necessary. Serve hot, optionally with rice or couscous.