Pre-heat the oven to 425 degrees and get 2 large sheet pans out. Do not spray or line the sheet trays.
Toss the quartered yellow potatoes on one of the sheet trays with 2 tablespoons of the reserved lemon garlic marinade and about ¼ to ½ tsp of sea salt to taste.
Roast the potatoes at 425 degrees for 15 minutes, and then give them on a stir on the sheet tray. S
Scoot the potatoes to one half of the sheet tray, and add the broccoli florets to the other side. Toss the broccoli florets with the other 2 tablespoons of lemon garlic marinade and sprinkle a few pinches of sea salt.
On the second sheet tray, line up the marinated chicken thighs, and then put both sheet trays into the oven together to roast for 25 minutes.