Preheat oven to 425°.
Heat a large skillet over high heat. Add the oil and the chickpeas and cook until browned, about 4 minutes. Do not leave unattended.
Add the Brussels sprouts and cauliflower, season with salt and pepper and add the thyme. Cook stirring until lightly browned.
Transfer the skillet to the oven and roast the vegetables for another 15 minutes or tender. Stir half way thru the oven roasting.
Squeeze the lemon juice and serve immediately.