Bring a medium pot of salted water to a boil and cook the whole wheat penne according to package directions until al dente.
During the last 3 minutes of pasta cooking, add the broccoli florets to the same pot to blanch them until bright green and tender-crisp.
Reserve 0.25 cup of the starchy pasta water, then drain the pasta and broccoli and set aside.
While pasta cooks, season the chicken breast with sea salt, black pepper, and onion powder.
Heat olive oil in a skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden brown and cooked through, then slice into strips.
In the same skillet, reduce heat to low and add the minced garlic, sautéing for 30 seconds until fragrant.
Whisk together the Greek yogurt, parmesan cheese, and the reserved pasta water in a small bowl until smooth.
Add the pasta, broccoli, and chicken back into the skillet and pour the yogurt mixture over the top.
Toss everything gently over low heat for 1 minute until the sauce coats the pasta evenly without boiling the yogurt.
Garnish with freshly chopped parsley and serve immediately.