Using a paper towel, pat-dry your tilapia fillets.
Chop up your broccoli, zucchini and onion in large pieces.
Place your vegetables in the sheet pan and drizzle with olive oil and lemon juice (preferably from a freshly squeezed lemon). Generously season your vegetables with salt, ground black pepper, tajin, granulated garlic and paprika. Toss your vegetables to ensure your seasonings combine well. Make sure to save half of your seasoning mixture to season the tilapia.
Move your vegetables aside to make room for the tilapia. Place your tilapia fillets on the sheet pan and drizzle with olive oil and lemon juice. Season generously with the rest of you salt, ground black pepper, tajin, granulated garlic and paprika on both sides. Cover with aluminum foil.
Place your covered sheet pan into a 400 degree preheated oven. Bake for 20 minutes. After 20 minutes, remove the aluminum foil cover and raise the temperature to 450 degrees. Bake at 450 degrees for 3-5 minutes.
Your healthy sheet pan tilapia and vegetables meal is ready to be served.