The short answer
Yes — broccoli is a nutritious daily vegetable; florets and leaves are both good.
Why
Broccoli is rich in vitamins and a useful source of calcium. Some budgies prefer it raw, others take to it lightly steamed — both are fine.
How to feed it
Offer a small floret or a chopped piece of stem, raw or lightly steamed and cooled.
How much & how often
Daily is fine.