It depends on which Nutro you are feeding. I feed my dog Nutro Large Breed Adult Lamb and Rice, which has plenty of it. So, for example, I wouldn't add rice to his food. When cooked, rice is the most digestible grain.
 
Kudos on the homecooking. I guess, maybe, you were wondering if you should add rice to the homecooked recipe. You can't get better advice than Glenda's. She's been there and done that on everything you can think of.
 
And Charlie is technically correct, in that they haven't yet defined a carb requirement for dogs. But dogs can and do process them. And vegetables and fruits have plenty of carbs in them, not just grain. Dogs that are active or working will use up those carbs in a hurry.