Bring a large pot of salted water to a boil and cook the penne according to package directions until al dente.
Before draining the pasta, reserve approximately 2 tablespoons of the starchy pasta water.
Heat the olive oil in a large skillet over medium-high heat.
Add the ground chicken to the skillet, breaking it up with a wooden spoon, and cook until browned and cooked through.
Stir in the minced garlic, sea salt, black pepper, and dried oregano, cooking for another 1 minute until fragrant.
Add the baby spinach to the skillet and stir until just wilted, then remove the skillet from the heat.
In a small bowl, whisk the Greek yogurt with the reserved pasta water to create a smooth, thin consistency.
Add the cooked penne to the skillet with the chicken and spinach.
Pour the yogurt mixture over the pasta and toss everything together until evenly coated and creamy.
Garnish with freshly chopped parsley and serve immediately.