Begin by patting the chicken breast dry with paper towels to ensure a good sear. Season it generously with salt, black pepper, and half of the dried oregano. Set aside for about 5 minutes, allowing the flavors to penetrate the meat before cooking.

In a large skillet, heat 2 tablespoons of olive oil over medium-high heat. Once the oil is shimmering, carefully add the seasoned chicken pieces. Sear the chicken for 5-6 minutes until golden brown on one side, then flip to cook the other side for an additional 3-4 minutes. Transfer the chicken to a plate after cooking and keep it warm.

In the same skillet, add the remaining tablespoon of olive oil and bring it back to medium heat. Add minced garlic and sauté for about 30 seconds until fragrant, being careful not to let it burn. Next, introduce the diced red bell pepper and sliced yellow squash to the skillet, cooking them for 4-5 minutes until they start to soften and blister.

Add the halved cherry tomatoes to the pan and continue to cook for an additional 2 minutes. Return the browned chicken to the skillet, then fold in the fresh spinach along with the remaining oregano and red pepper flakes. Toss everything together and sauté for 2-3 minutes until the spinach has wilted and all components are heated through.

Remove the skillet from heat and zest a lemon over the stir fry to add a bright finish. Taste and adjust the seasoning with additional salt and pepper if desired. Serve your Mediterranean Chicken Stir Fry hot, optionally over a bed of rice or couscous.