Yes of course you can!As long as you get the balance right for your blood glucose you can eat whatever you want.sometimes that means a very small portion,other times a large one.I frequently have a bowl of veg topped with grated cheese for lunch.
Making your own cheese sauce would give you better control.

Broccoli and cheese sauce not many carbs at all..depends on what you use for the Casserole base. I found some almond flour noodles with very few carbs that I use. Other members have their low carb favorites maybe they'll chime in.

Of course you can in moderation, its all about substitutions, if you over do it on one meal simply slack off on the next. I'm sure other people have the stats on broccoli and the cheesey sauce (oh, I'm hungry now) but see what your meter says before and two hours after.